The US Marine Corps has the most stable and most recognizable uniforms in the American military; the Blue Dress dates back to the early 19th century and the service uniform to the early 20th century. Marines' uniforms are also distinct in their simplicity; Marines do not wear unit patches or United States flags on any of their uniforms, nor name tags on their service and formal uniforms. Only a handful of skills (parachutist, air crew, explosive ordnance disposal, etc.) warrant distinguishing badges, and rank insignia is not worn on uniform headgear (with the exception of an officer's garrison service cover). While other servicemembers commonly identify with a sub-group as much as or more than their service (Ranger, submariner, aircrew, etc.), Marine uniforms do not reflect such division.

Marines have three main uniforms: Dress, Service, and Utility. The Marine Corps Dress uniform is the most elaborate, worn for formal or ceremonial occasions. There are three different forms of the Dress uniform, the most common being the Blue Dress Uniform, also called "Dress Blues" or simply "Blues". It is most often seen in recruiting advertisements and is equivalent to black tie. There is also a "Blue-White" Dress for summer, and Evening Dress for formal (white tie) occasions. Versions with a khaki shirt in lieu of the coat are worn as a daily working uniform by Marine recruiters.

The Service Uniform was once the prescribed daily work attire in garrison; however, it has been largely superseded in this role by the utility uniform. Consisting of olive green and khaki colors, it is commonly referred to as "Greens". It is roughly equivalent in function and composition to a business suit.

The Utility Uniform, currently the Marine Corps Combat Utility Uniform, is a camouflage uniform intended for wear in the field or for dirty work in garrison, though it has now been standardized for regular duty. It is rendered in a distinctive MARPAT pixelated camouflage (sometimes referred to as digitals or digies) that breaks up the wearer's shape, and also serves to distinguish Marine uniforms from those of other services. In garrison, the woodland uniform is worn sleeves down in winter, and the desert uniform is worn with sleeves rolled up in summer. The sleeves are rolled tightly to the biceps, exposing the lighter inside layer, and forming a neat cuff to present a crisper appearance to the otherwise formless uniform. In years past when Marines wore identical utilities to their Army and Air Force counterparts, this served to distinguish them as the other services have a different practice for rolling sleeves. Marines consider the utilities a working uniform and do not permit their wear off-base, except in transit to and from their place of duty and in the event of an emergency. This, too, distinguishes them from other services, which have less stringent restrictions.

US Marine Corps Dress uniform

The Marine Corps dress uniform is an elaborate uniform worn for formal or ceremonial occasions. Its basic form of a blue jacket with red trim dates back to the 19th century. It is the only U.S. military uniform that incorporates all three colors of the U.S. Flag. There are three different variations of the Dress uniform: Evening Dress, Blue Dress, and Blue-White Dress; only officers and SNCOs are authorized to wear the Evening Dress. Until 2000, there was a White Dress uniform, similar in appearance to the U.S. Navy's Dress White uniforms, but worn by officers only (in a manner similar to that of the Dress White uniforms worn in the U.S. Coast Guard). This uniform has since been replaced with the Blue/White Dress uniform for officers and SNCOs.

Blue Dress

The most recognizable uniform of the Marine Corps is the Blue Dress uniform, often seen in recruiting advertisements. It is often called "Dress Blues" or simply "Blues". It is equivalent in composition and use to civilian black tie. The various designations are listed in descending order of formality:

• Blue Dress "A" has a long-sleeved midnight blue coat (enlisted members have red trim) with a standing collar and belt (white web belt and gold waistplate for enlisted; midnight blue for officers with a gold M-buckle), white barracks cover (a peaked cap), plain white shirt, sky blue trousers (midnight blue for general officers), white gloves, and black dress shoes and socks. Full-size medals are worn on the left chest, with ribbon-only awards worn on the right. Marksmanship badges are not worn. Women wear pumps in place of shoes, and may wear a skirt in place of slacks. For men, the dress coat is cut to be formfitting.
• Blue Dress "B" is the same as "A", but medals are replaced with their corresponding ribbons and all are consolidated on the left chest. Marksmanship badges may be worn.
• Blue Dress "C" is the same as "B", but a khaki long sleeve button-up shirt and tie replace the outer blue coat and white gloves. Ribbons and badges are normally worn on the shirt.
• Blue Dress "D" is the same as "C", but with a khaki short sleeve button-up shirt and no tie.

Because the Blue Dress uniform is considered formal wear, Blue Dress "C" and "D" are rarely worn. The main exception are Marine Recruiters and Marine Corps Security Guards, who wear the "C" and "D" in warm weather. Only the "B", "C", and "D" Blue Dress uniforms are authorized for leave and liberty wear; the "A" is not.

Officers, NCOs, and SNCOs wear a scarlet "blood stripe" down the outer seam of each leg of the blue trousers. General officers wear a 2 in (5.1 cm) wide stripe, field- and company-grade officers have a 1.5 in (3.8 cm) wide stripe, SNCOs and NCOs have a 1.125 in (2.86 cm) wide stripe. General officers wear trousers that are the same color as the coat, while all other ranks wear medium (sky) blue trousers. A blue boatcloak with a scarlet lining is optional.

A blue crewneck sweater, in the same color shade as that of the trousers, may be worn with the "C" and "D" uniforms, in which case rank insignia will continue to be worn on the collar by officers, and all wearers will display rank insignia on shoulder epaulettes (polished brass for enlisted). The collar is worn on the outside of the sweater in order to display the rated rank insignia of officers. When wearing the crewneck sweater with the long sleeve khaki shirt, a tie is not required.

Blue-White Dress

Prior to 1998, the "Blue-White" dress uniform was authorized to be worn for the ceremonial units at Marine Barracks, 8th & I in Washington, D.C. (most famously the Silent Drill Platoon and Color guard). Since then, it has become the authorized summer dress uniform for all officers (it replaced, in 2000, an all-white uniform, similar in appearance to that of the Naval Officer/CPO white dress uniform), SNCOs (unless they are in formation with NCOs and junior enlisted personnel who are not authorized to wear the uniform), and by NCOs and junior enlisted personnel for ceremonies and social events only, if authorized and provided by the command structure.

Like the Blue Dress uniform, the Blue-White Dress consists of an "A" and "B" uniform, and is worn in the same manner as that of the Blue Dress uniform, except for the trousers, skirt, or slacks being white instead of blue. Unlike the Dress Blues, the Blue-White Dress uniforms do not feature the "blood stripe". As with the Dress Blues, the "A" is not authorized for leave and liberty wear. The white trousers are not authorized for wear with either the long-sleeved or the short-sleeved khaki shirt, precluding the "C" and "D" uniforms.

Red Dress

To differentiate themselves from the infantry, musicians—at that time, merely buglers and signal callers—would reverse the traditional colors. Today's Marine Corps musicians still carry on this tradition by wearing a scarlet blouse with blue trim instead of the Dress Blues blouse. Currently, the Red-Dress uniform is worn only by members of the United States Marine Band and the United States Marine Drum and Bugle Corps, both based in Washington, D.C.; members of the twelve fleet bands wear standard Marine uniforms.

Like the Blue-White Dress uniform, musicians are not authorized to wear the khaki shirts with the Red-Dress uniform. Should the condition warrant (e.g., summer heat), the band will wear the appropriate Dress or Service uniforms.

Evening Dress

The Evening Dress is the most formal (and by U.S. Military standards, the most elaborate) of the Dress uniforms, and is the equivalent of white tie in usage. It is only authorized for wear by officers and SNCOs, and only a required uniform item for senior officers (Majors and above). It comes in three varieties:

• Evening dress "A" (for officers) is similar to Dress Blue "A", except an evening coat with strip collar, white waistcoat, and white shirt with pique placket is worn. The stripe on the trousers is a thin red stripe inside a gold embroidered stripe. Women wear a long skirt. Miniature medals and badges are worn.
• Evening dress "B" is identical to Evening Dress "A" except men wear a scarlet waistcoat (General officers) or cummerbund (other officers), and women may wear a short skirt.
• SNCO Evening Dress for Staff Non-Commissioned Officers, and much resembles a tuxedo with historic 1890s-era rank insignia sewn on the sleeves.

A blue boatcloak with a scarlet silk liner is optional. Junior officers not required to possess Evening Dress may substitute Blue or Blue-White dress "A". It is appropriate for such occasions as State functions, inaugural receptions and dinners, and formal dinners.

US Marine Corps Service uniform

The service uniform consists of green and khaki colors. It is roughly equivalent in function and composition to a business suit. It is the prescribed uniform when

• serving on a court-martial
• making official visits and calls on American and foreign dignitaries, officials, and military officers.
• visiting the White House, except when in a tourist capacity, or on an occasion where another uniform is specified.
• reporting for duty onshore

Like the Blue Dress uniform, the service uniform is authorized for wear while off-duty (i.e., while on leave or liberty).

The service uniforms are designated:

• Service "A" (or Alpha) is the base uniform. It consists of a green coat, green trousers with khaki web belt, khaki long-sleeve button-up shirt, khaki tie, tie clasp, and black shoes. The coat is cut to be semi-form fitting, with ribbons and marksmanship badges worn on the left chest of the coat. Women wear a green necktab in place of the tie, pumps instead of shoes, and have the option of wearing a skirt instead of slacks. It is sometimes appropriate to remove the jacket while indoors.
• Service "B" (or Bravo) is identical to the "A" except the coat is removed. Ribbons may be worn on the shirt.
• Service "C" (or Charlie) is identical to the "B" except with a short-sleeve button-up shirt and no tie.

There are two types of authorized headwear for the service uniform. Both men and women may wear the green soft garrison cap, sometimes nicknamed a "piss cutter". There is the option of wearing a hard-framed service cap (called a Barracks Cover). The design of these covers differ between women and men. As on the Blue Dress uniform, officers wear rank insignia on the shoulder epaulettes of their jackets and the collars of their shirts, while enlisted personnel wear rank insignia sewn on their sleeves.

A green crewneck sweater may be worn with the "B" and "C" uniforms, in which case rank insignia will continue to be worn on the collar by officers and all ranks will wear rank insignia on shoulder epaulettes (black for enlisted). The collar is worn on the outside of the sweater in order to display the rated rank insignia of officers. When wearing the crewneck sweater with the long sleeve khaki shirt, a tie is not required.

US Marine Corps Utility uniform

The Marine Corps Combat Utility Uniform or MCCUU is intended for wear in the field or for working parties, but has become the typical working uniform for all deployed and most garrison Marines and Sailors. It is rendered in MARPAT digital camouflage that breaks up the wearer's shape, and also serves to distinguish Marine uniforms from those of other services. Previously, Marines wore the same utility uniforms as the Army. It consists of MARPAT blouse and trousers, green undershirt, and tan (specifically "olive mojave") suede boots. There are two approved varieties of MARPAT, woodland/winter (green/brown/black) and desert/summer (tan/brown/grey). To further distinguish the uniform, upon close examination, the Eagle, Globe, and Anchor can be found within the pattern.

The variety worn depends on the environment and season: Deployed Marines wear whichever color is more appropriate to the climate and terrain, Marines in garrison wear the woodland MCCUU with long sleeves in winter months, and the desert MCCUU with sleeves rolled up in summer months (the transition occurs simultaneously with Daylight Saving Time). When rolled, the sleeves of the blouse are tightly folded up to the biceps, exposing the lighter inside layer, and forming a neat cuff to present a crisper appearance to the otherwise formless uniform. In the past, when Marines wore the same utilities as the Army and Air Force, this served to distinguish them from the other branches, who folded the sleeves in with the camo facing out. In Haiti, the practice earned them the nickname "whitesleeves".

Both officers and enlisted wear rank insignia on each collar, which is affixed like a pin and not sewn on as in the Army/Air Force. Enlisted insignia is always black, while officers wear bright metal insignia in garrison and subdued insignia (or none at all) in the field. Most badges and breast insignia are authorized for wear on the utility uniform, shined or subdued as appropriate. Landing Support Marines also wear the Red Patch insignia.

Unlike the dress and service uniforms, utility uniforms are not permitted for wear on leave or liberty (i.e., while off-duty), except when traveling in a vehicle between a place of duty and a residence, or in emergency stops.

The approved headwear is the utility cover, an eight-pointed brimmed hat that is worn "blocked", that is, creased and peaked. In the field, a boonie cover is also authorized. The trouser legs are "bloused", or the cuffs are rolled inside and tightened over their boots with a spring or elastic band known as a "boot band" or "blousing garter". With the introduction of the Marine Corps Martial Arts Program (MCMAP), Marines now wear color-coded rigger's belts instead of the old web belt, indicating their level of proficiency in MCMAP (the web belt was phased out in 2008 due to a requirement for all Marines to achieve a tan belt rank by then).

In combat, Marines will also wear one of two ballistic vests: the Outer Tactical Vest and the newer Modular Tactical Vest, as well as the Lightweight Helmet (replacing the PASGT helmet) and Improved Load Bearing Equipment. Marines in a combat area may also wear Flame resistant organizational gear, or FROG uniforms. These combat uniforms are designed to reduce fire-related injuries, and look quite similar to the MCCUU. Other individual equipment may be worn as directed.

The wearing of the MCCUU by civilian contractors deploying with Marine units was granted early in the Iraq War, but rescinded in early 2008.

US Marine Corps Physical training uniform

The Physical training uniform or PT uniform consists of one of the following pairs:

• green nylon shorts and cotton t-shirt (shirts with unit logos can be authorized)
• green sweatpants and sweatshirt with the Marine Corps emblem printed in black on the left chest and thigh
• The green tracksuit with gold and scarlet "Marines" lettering and reflective trim was unveiled during a tour of Iraq in December 2007, by Commandant of the Marine Corps General James Conway. It began to be issued to Marines free of charge in February 2008 and will be mandatory possession by the end of FY 2010.

In addition, Marines can wear a watch cap and gloves in cold weather, or a hydration pack to prevent dehydration.

Boot camp is a thirteen week cycle of training, beginning with a receiving phase of in-processing or "forming", followed by three numbered phases. Each phase includes intensive education and training on various topics essential for military life. Each phase consists of a predetermined number of training days, these are counted in the training matrix as "T1", "T2", up to "T70" which is Graduation Day.

US Marine Corps Training: Receiving Phase

The initial period of Marine Corps Boot Camp is called the Receiving Phase, which begins as the new recruits are on the bus en route to their recruit Depot. They are greeted by a drill instructor, who acquaints them with the Uniform Code of Military Justice, to which they are now subject. Disembarking from the bus, they line up on the famous "yellow footprints", which is their first formation and learn how to stand at attention.

The recruits are given the opportunity to phone their next of kin and inform them of the recruit's safe arrival, then are searched for contraband. They are issued utility and physical training uniforms and toiletries. From here, the males receive their first military haircut, where they are left essentially bald. Females are instructed in the authorized hairstyling, which allows hair to be short enough to not touch the collar or in a bun.

The remainder of receiving involves completing paperwork, issuing a M16A2 service rifle, receiving vaccines and medical tests, and storing civilian belongings under the eye of drill instructors set aside specifically for receiving. This takes approximately three days, usually without the opportunity to sleep, and ends with the Initial Strength Test (IST). The IST is a shortened form of the PFT to assess if a recruit is physically fit enough to begin training. To pass, a male recruit must complete at least 2 pull-ups, 35 crunches in two minutes, and run 1.5 miles in 13:30 minutes or less. The female recruits must hold a “flexed arm hang” (hanging on a bar with their arms bent) for at least 12 seconds, complete 35 crunches in two minutes, and run 1.5 miles in 15 minutes or less.

From this point, recruits experience "Black Friday", where they meet their permanent Drill Instructors. They also meet their Company Commander, usually a captain, who orders their Drill Instructors to train them to become Marines and has them recite the Drill Instructor's Creed. At this point recruit training truly begins. Recruits are familiarized with incentive training as one of the consequences of disobedience or failure to perform to a Drill Instructor's expectations. The Drill Instructors physically, psychologically, and mentally challenge the recruits, including yelling at maximum volume and intimidation, to simulate stress of the battlefield and elicit immediate compliance to instructions. The remainder of receiving is made as confusing and disorienting for the recruits as possible, to help distance the recruits from civilian habits and to prepare them for Marine Corps discipline.

It is at this point that a recruit must come to terms with the decision he or she has made and develop the true determination needed to make it through the process of becoming a United States Marine. The final "moment of truth" is offered to those who have been dishonest about their eligibility, such as drug use, judicial convictions, or other disqualifying conditions.

US Marine Corps Training: Phase One

Phase One lasts approximately four weeks. Here, discipline will begin to be instilled in recruits by disorienting them and effectively cutting them off from civilian habits and mindsets, as well as reinforcing the mental and physical standards needed to perform under stressful situations that will be simulated in subsequent phases, and experienced in combat situations. Recruits are required to learn and strictly use language and terminology typical to the Marine Corps, often derived from naval terminology.

The purpose of the first phase is not only to physically challenge, but also to psychologically break down the recruit. At this point, civilian thoughts and habits are considered detrimental to training, so they are squashed during this period by intense physical training, unchanging routines, strict discipline, and heavy instruction. The process is designed to enable recruits to learn to survive in combat situations and generally to adapt and overcome any unexpected situation. One of the principal ideals learned during this period is that recruits are not to think of themselves as individuals; they are not permitted to use first person or second person pronouns. Instead, recruits are required to use third-person referrals, such as referring to themselves as "This recruit" and accomplish all tasks with teamwork. Any actions that put the benefit of an individual over the benefit of the other recruits are not permitted, and recruits are expected to conform to a standard that does not tolerate personal deviance or eccentricities. Speed, intensity and volume when speaking are valued as well.

The bulk of first-phase education consists of classes about the Marine Corps and its history and culture, first aid, rank structure and insignia, protocol, customs and courtesies, the 11 General Orders, aspects of the five paragraph order, prepare equipment for use (such as how to properly make a rack), regulations regarding uniforms, and other topics. Recruits learn through the use of rote memorization and mnemonics; recruits are expected to be able to recite a passage or quote in unison, without error, and on demand.

Close order drill is an important factor in recruit training, and begins from their first formation on the yellow footprints. In the first phase, they learn all of the basic commands and movements, memorizing the timing through the use of "ditties", or mnemonics, that help synchronize a recruit's movements with the rest of his or her platoon. Constant repetition and practice are used to facilitate muscle memory, so that any given movement can be rendered immediately and accurately upon order without hesitation. To aid in this development, drill movements are worked into other parts of daily life, to help increase the platoon's synchronization and muscle memory; this same technique is used with other non-drill activities as well. The first inter-platoon contest, held in the last week of the first phase, is termed "initial drill", where the platoon and junior-most drill instructor are graded as a whole on their performance in close order drill.

During this phase, recruits are familiarized with their rifle. This weapon, never referred to as a "gun", stays with the recruit through the entirety of recruit training, being locked to his or her rack at night, while platoons will stack weapons together under guard for activities where retaining it is impractical, such as swimming. Recruits must memorize the rifle's serial number, the four weapons safety rules, the four weapons conditions, and go through preparatory lessons in marksmanship. In addition, recruits use the rifles in close order drill, and will spend considerable time cleaning their weapons.

Recruits begin work toward earning their tan belt in the Marine Corps Martial Arts Program. Physical fitness gradually becomes more and more intense as recruits begin to get stronger and their bodies accustomed to the strain. Recruits undergo the first of their conditioning marches, which will grow in length. Periodic fitness tests assess which recruits need more attention, and those who consistently fail to meet the minimum are in danger of being sent to the PCP. Recruits will conduct two pugil stick bouts and are introduced to the obstacle course.

By the end of the first phase, recruits can march, respond to orders, pass the first written test, and keep up in physical fitness.

US Marine Corps Training: Phase Two

Phase Two of recruit training is an introduction to field skills, and includes two weeks of marksmanship training, a field week, and "Team Week".

In the first week of the second phase, recruits are taught swimming and water survival. This is the first event where failure to pass will result in a recruit being dropped to a different company to restart training and attempt to qualify again. If a recruit fails twice, he or she will be evaluated to see if a third chance is warranted, or if the recruit will be deemed unable to qualify and administratively separated from service.

The second week is known as "Grass Week". This week is partly spent in a class setting to learn about marksmanship principles of the M16A2 and how to shoot efficiently. When not in class, recruits are snapping in, or practicing their firing positions. Recruits are taught how to shoot by a Primary Marksmanship Instructor, a Marine of the MOS 0931. While range personnel wear campaign covers similar to drill instructors, PMIs are not drill instructors and generally not as strict in enforcing discipline upon recruits, focusing on marksmanship and expecting recruits to uphold their own discipline.

The third week is called "Firing Week", which ends with Qualification Day. This week recruits are awakened early in the morning to prepare the rifle range for firing. They spend all day running through the Known Distance Course of fire (also known as table 1), in order to practice their marksmanship skills with live rounds. Half of the platoons will fire at the 200, 300 and 500 yard lines (182.88, 274.32 and 457.2 meters), in the standing, sitting, kneeling and prone positions; the other half will mark targets in the pits. Friday of that week is qualification day, where recruits must qualify with a minimum score in order to earn a marksmanship badge and continue training. Those who fail to qualify are given a second opportunity during Team Week; if they fail again, they are dropped and will repeat Grass Week. The Marines are the only branch of the United States armed forces that require the 500 yard line qualification. A trophy is awarded to the platoon with the highest cumulative scores.

After the rifle range, recruits begin Team Week. During this week, recruits are placed in various service jobs around the depot, such as yard work, cleaning, maintenance, etc. During this week, recruits will be able to revisit previous instruction and retake tests. Recruits that need to have medical or dental needs addressed, such as the extraction of wisdom teeth, have those procedures done here so that recovery time impacts training as little as possible. Recruits are also fitted for their service and dress uniforms.

Many companies choose to end team week with a weekend "field meet", where platoons will compete in several military-related sports events, such as a rifle assembly race, sprints, a short marathon, an obstacle course race, and a tug of war.

Because MCRD San Diego is located in the center of a dense urban area, it is impractical to conduct rifle qualification and field training there. Instead, recruits are sent to the Edson Range at Marine Corps Base Camp Pendleton for three weeks during the second phase. At the conclusion, they are returned to MCRD San Diego to continue training.

US Marine Corps Training: Phase Three

Phase Three is essentially the 'polishing' of the recruits, when their skills and knowledge are honed and tested.

Third phase begins with A-line, where recruits learn to fire their rifle under more realistic combat conditions, such as unknown distances, at night, and wearing a gas mask.

The next week sees recruits at Basic Warrior Training (BWT), where they learn the fundamentals of combat and will sleep in the field and eat MREs. Skills taught include camouflage, low crawling, land navigation, basic squad tactics, rapelling, and other foundations of military skills. BWT ends with the gas chamber, where recruits must don and clear their gas mask while exposed to CS gas, in order to be confident in its use in case of exposure to a lethal agent. Recruits who attempt to flee from the chamber before finishing or refuse to enter are dropped.

After this week, recruits return to garrison for the final drill competition, take the final PFT, and take the final written test (which culminates all of their academic and classroom topics); each event has a trophy for the highest-scoring platoon. At this point, recruits will take their MCMAP test and earn their tan belt; those who fail are dropped. Recruits then prepare for the Crucible.

The Crucible

The Crucible is the final test in recruit training, and represents the culmination of all of the skills and knowledge a Marine should possess. Designed in 1996 to emphasize the importance of teamwork in overcoming adversity, the Crucible is a rigorous 54-hour field training exercise demanding the application of everything a recruit has learned until that point in recruit training, and includes a total of 48 miles of marching. It simulates typical combat situations with strenuous testing, hardship, and the deprivation of food and sleep. A recruit is given three MREs (previously two and half) and four to eight hours of sleep through the entire 54-hour event. For this event, recruits are broken into squad-sized teams (possibly smaller) and placed under the charge of one drill instructor. West Coast recruits are returned to Edson Range for the Crucible. Parris Island recruits will conduct the Crucible in the derelict Page Airfield on the south end of the depot.

Throughout the Crucible, recruits are faced with physical and mental challenges that must be accomplished before advancing further. Teamwork is stressed, as the majority of tasks are completely impossible without it; each group must succeed or fail as a whole. The others will result in failure unless every recruit passes through together, requiring the team to aid their fellow recruit(s) who struggle in the accomplishment of the given mission. Also stressed are the Corps' core values of Honor, Courage, and Commitment; events sometimes present a moral challenge. Many challenge events are named after Marine Medal of Honor recipients or otherwise notable Marines, and drill instructors will often take the time to read the citation of the award and hold a guided discussion with the recruits to evaluate their moral development. Drill instructors are also vigilant for those recruits who succeed and fail in leadership positions.

Some of the challenges encountered during the Crucible are various team and individual obstacle courses, day and night assault courses, land navigation courses, individual rushes up steep hills, large-scale martial arts challenges, and countless patrols to and from each of these. Often, these challenges are made even more difficult by the additions of limitations or handicaps, such as the requirement to carry several ammunition drums, not touching portions of an obstacle painted red to indicate simulated booby traps, and evacuating team members with simulated wounds.

On the final day of the Crucible, recruits are awoken and begin their final march (known as the "Reaper" march on the west coast). Immediately following this, recruits are offered the "Warrior's Breakfast", where they are permitted to eat as much as they like, even of previously forbidden foods, such as ice cream. Following this is the Eagle, Globe, and Anchor ceremony, where the recruits receive the eponymous emblem, and thereby cease to be recruits, finally becoming Marines. In recent years, this ceremony has been moved to the day before graduation, and signals the start of Family Day.

US Marine Corps Training: Graduation

The final week of Recruit Training is referred to as "Marine Week" and includes the Battalion Commander's Inspection, Family Day, and Graduation. During this week, Marines are instructed in some of the recruit behaviors that are no longer appropriate as Marines, such as referring to self in the third person. Final photos are taken, a representative from the School of Infantry will conduct a brief, and travel arrangements are made for a ten day leave.

The last full day before graduation is called Family Day. The public day begins early with a "Motivational Run", when the new Marines run (by company, then by platoon) yelling Marine Corps Cadences, past their families; circling the base and ending at the parade deck. The newest Marines are dismissed to on-base liberty with their families from late morning until early evening. During the last night, some platoons allow the recruits to host a gong show, where they perform skits regarding humorous moments during training, especially of their drill instructors. Some drill instructors will use this as an excuse to perform incentive training on their platoon one last time.

The next morning, the new Marines form for their graduation ceremony, march across the parade deck, and are dismissed from recruit training by their senior drill instructors.

Every year, over 2,000 new Marine officers are commissioned, and 38,000 recruits accepted and trained. All new Marines, enlisted or officer, are recruited by the Marine Corps Recruiting Command.

Commissioned officers are commissioned mainly through one of three sources: Naval Reserve Officer Training Corps (NROTC), Officer Candidates School (OCS), or the United States Naval Academy (USNA). Following commissioning, all Marine commissioned officers, regardless of accession route or further training requirements, attend The Basic School (TBS) at Marine Corps Base Quantico, Virginia. At TBS, second lieutenants, warrant officers, and selected foreign officers learn the art of infantry and combined arms warfare. Along with the concept that "Every Marine is a rifleman", every officer, regardless of his MOS/billet, is qualified to be an infantry platoon commander.

Enlisted Marines attend recruit training, known as boot camp, at either Marine Corps Recruit Depot San Diego or Marine Corps Recruit Depot Parris Island. Historically, the Mississippi River served as the dividing line which delineated who would be trained where, while more recently, a district system has ensured a more even distribution of male recruits between the two MCRD facilities. Females attend only the Parris Island depot as part of the segregated Fourth Recruit Training Battalion. All recruits must pass a fitness test to start training; those who fail receive individualized attention and training until the minimum standards are reached. Marine recruit training is the longest among the American military services; it is 13 weeks long, compared to the Army's 10 weeks or the Navy's 9 weeks.

Following recruit training, enlisted Marines then attend School of Infantry training at Camp Geiger or Camp Pendleton. Infantry Marines begin their combat training, which varies in length, immediately with the Infantry Training Battalion (ITB). Marines in all other MOSs other than infantry train for 29 days in Marine Combat Training (MCT), learning common infantry skills, before continuing on to their MOS schools which vary in length.

United States Marine Corps Recruit Training, commonly known as "boot camp", is a program of initial training that each recruit must successfully complete in order to join the United States Marine Corps. All enlisted individuals entering the Marine Corps, regardless of eventual active or reserve duty status, will undergo recruit training at one of the two Marine Corps Recruit Depots (MCRD): Parris Island, South Carolina, or San Diego, California. Male recruits from the 8th, 9th and 12th recruiting districts (predominantly areas west of the Mississippi River) are sent to MCRD San Diego. Male recruits from 1st, 4th and 6th recruiting districts, as well as all female recruits, are sent to Parris Island.

Those desiring to become officers attend training at Officer Candidates School, United States Naval Academy, or Reserve Officer Training Corps.

Marines generally hold that their recruit training is the most physically and mentally difficult amongst the Uniformed Services, often by citing that it is longer, a more demanding Physical Fitness Test (PFT), and the strictest height and weight standards.

As in the rest of the United States military, Marine Corps ranks fall into one of three categories: commissioned officer, warrant officer, and enlisted, in decreasing order of authority (excluding the Air Force, which does not currently appoint warrant officers). To standardize compensation, each rank is assigned a pay grade.

US Marine Corps Rank Insignia: Commissioned Officers

Commissioned Officers are distinguished from other officers by their commission, which is the formal written authority, issued in the name of the President of the United States, that confers the rank and authority of a Marine Officer. Commissioned officers carry the "special trust and confidence" of the President of the United States. Commissioned officer ranks are further subdivided into general officers, field officers, and company-grade officers. The Commandant of the Marine Corps and the Assistant Commandant of the Marine Corps are, by statute, 4 star ranks.

General officers
General (Gen)	Lieutenant General (LtGen)	Major General (MajGen)	Brigadier General (BGen)
O-10	O-9	O-8	O-7

Field officers			Company-grade officers
Colonel (Col)	Lieutenant Colonel (LtCol)	Major (Maj)	Captain (Capt)	First Lieutenant (1stLt)	Second Lieutenant (2ndLt)
O-6	O-5	O-4	O-3	O-2	O-1

US Marine Corps Rank Insignia: Warrant Officers

Warrant Officers provide leadership and training in specialized fields and skills. Unlike most other militaries, the United States military confers warrants and commissions on its Warrant Officers, though they are generally not responsible for leadership outside of their specialty. Warrant officers come primarily from the senior Non-Commissioned Officer ranks.

A Chief Warrant Officer, CWO2-CWO5, serving in the MOS 0306 "Infantry Weapons Officer" carries a special title, "Marine Gunner", which does not replace his rank. A Marine Gunner replaces the Chief Warrant Officer insignia on the left collar with a bursting bomb insignia. Other warrant officers are sometimes informally also referred to as "Gunner".

Warrant Officers
Chief Warrant Officer-5 (CWO5)	Chief Warrant Officer-4 (CWO4)	Chief Warrant Officer-3 (CWO3)	Chief Warrant Officer-2 (CWO2)	Warrant Officer (WO)	Infantry Weapons Officer "Marine Gunner"
W5	W4	W3	W2	W1	varies

US Marine Corps Rank Insignia: Enlisted

Enlisted Marines with paygrades of E-4 and E-5 are considered non-commissioned officers (NCOs) while those at E-6 and higher are considered Staff Noncommissioned Officers (SNCOs). The E-8 and E-9 levels each have two ranks per pay grade, each with different responsibilities. Gunnery Sergeants (E-7) indicate on their annual evaluations (called "fitness reports") their preferred promotional track: Master Sergeant or First Sergeant. The First Sergeant and Sergeant Major ranks are command-oriented Senior Enlisted Advisors, with Marines of these ranks serving as the senior enlisted Marines in a unit, charged to assist the commanding officer in matters of discipline, administration, and the morale and welfare of the unit. Master Sergeants and Master Gunnery Sergeants provide technical leadership as occupational specialists in their specific MOS. First Sergeants typically serve as the senior enlisted Marine in a company, battery, or other unit at similar echelon, while Sergeants Major serve the same role in battalions, squadrons, or larger units.

The Sergeant Major of the Marine Corps is a billet and special rank, conferred on the senior enlisted Marine of the entire Marine Corps, personally selected by the Commandant of the Marine Corps. It and the Marine Gunner are the only billets which rate modified rank insignia in place of the traditional rank insignia.

Staff Non-Commissioned Officers (SNCOs)
Sergeant Major of the Marine Corps	Sergeant Major (SgtMaj)	Master Gunnery Sergeant (MGySgt)	First Sergeant (1stSgt)	Master Sergeant (MSgt)	Gunnery Sergeant (GySgt)	Staff Sergeant (SSgt)
E-9			E-8		E-7	E-6

Non-commissioned Officers (NCOs)		Junior enlisted
Sergeant (Sgt)	Corporal (Cpl)	Lance Corporal (LCpl)	Private First Class (PFC)	Private (Pvt)
E-5	E-4	E-3	E-2	E-1
				no insignia

Different styles of rank insignia are worn on different Marine uniforms:

The gold stripes on red flash are worn on the Dress Blue coat, green stripes on red flash are worn on the Service "A" uniform coat; the rank insignia are worn on the upper sleeve of both coats. The khaki uniforms use green stripes on khaki flash, and again are worn on the upper sleeves of both long and short-sleeved service shirts. Utility uniform rank insignia are black metal pins and are worn on the collars. Musicians in the United States Marine Band wear insignia with the crossed rifles replaced by a lyre to denote their lack of a combat mission; full-service Marines who are attached to other bands continue to wear their normal rank insignia.

United States Marine Corps History: Origins

The United States Marine Corps traces its institutional roots to the Continental Marines of the American Revolutionary War, formed by Captain Samuel Nicholas at Tun Tavern in Philadelphia, by a resolution of the Second Continental Congress on 10 November 1775, to raise 2 battalions of Marines. That date is regarded and celebrated as the date of the Marine Corps' "birthday". At the end of the American Revolution, both the Continental Navy and Continental Marines were disbanded in April 1783. The institution itself would not be resurrected until 1798. In that year, in preparation for the Quasi-War with France, Congress created the United States Marine Corps. Marines had been enlisted by the War Department as early as August 1797 for service in the new-build frigates authorized by Congress. The "Act to provide a Naval Armament" of March 18, 1794 authorizing them had specified the numbers of Marines to be recruited for each frigate.

The Marines' most famous action of this period occurred during the First Barbary War (1801–1805) against the Barbary pirates, when William Eaton and First Lieutenant Presley O'Bannon led eight Marines and 500 mercenaries in an effort to capture Tripoli. Though they only reached Derna, the action at Tripoli has been immortalized in the Marines' hymn and the Mameluke Sword carried by Marine officers.

During the War of 1812, Marine naval detachments took part in the great frigate duels that characterized the war, which were the first American victories in the conflict. Their most significant contributions were delaying the British march to Washington, D.C. at the Battle of Bladensburg and holding the center of Gen. Andrew Jackson's defensive line at the defense of New Orleans. By the end of the war, the Marines had acquired a well-deserved reputation as expert marksmen, especially in ship-to-ship actions.

After the war, the Marine Corps fell into a depression that ended with the appointment of Archibald Henderson as its fifth commandant in 1820. Under his tenure, the Corps took on expeditionary duties in the Caribbean, the Gulf of Mexico, Key West, West Africa, the Falkland Islands, and Sumatra. Commandant Henderson is credited with thwarting President Jackson's attempts to combine and integrate the Marine Corps with the Army. Instead, Congress passed the Act for the Better Organization of the Marine Corps in 1834, stipulating that the Corps was part of the Department of the Navy as a sister service to the Navy. This would be the first of many times that the existence of the Corps was challenged.

Commandant Henderson volunteered the Marines for service in the Seminole Wars of 1835, personally leading nearly half of the entire Corps (two battalions) to war. A decade later, in the Mexican–American War (1846–1848), the Marines made their famed assault on Chapultepec Palace in Mexico City, which would be later celebrated by the phrase "From The Halls of Montezuma" in Marines' hymn. In the 1850s, the Marines would see further service in Panama and Asia, escorting Matthew Perry's East India Squadron on its historic trip to the Far East.

With their vast service in foreign engagements, the Marine Corps played a moderate role in the Civil War (1861–1865); their most prominent task was blockade duty. As more and more states seceded from the Union, about half of the Corps' officers also left the Union to join the Confederacy and form the Confederate States Marine Corps, which ultimately played little part in the war. The battalion of recruits formed for the First Battle of Bull Run (First Manassas) performed poorly, retreating with the rest of the Union forces.

United States Marine Corps History, Interim: Civil War to World War I

The remainder of the 19th century was marked by declining strength and introspection about the mission of the Marine Corps. The Navy's transition from sail to steam put into question the need for Marines on naval ships. Meanwhile, Marines served as a convenient resource for interventions and landings to protect American lives and interests overseas. The Corps was involved in over 28 separate interventions in the 30 years from the end of the American Civil War to the end of 19th century. They would also be called upon to stem political and labor unrest within the United States. Under Commandant Jacob Zeilin's tenure, Marine customs and traditions took shape: the Corps adopted the Marine Corps emblem on 19 November 1868. It was also during this time that "The Marines' Hymn" was first heard. Around 1883, the Marines adopted their current motto "Semper Fidelis" (English: Always Faithful).

John Philip Sousa, the musician and composer, enlisted as a Marine apprentice at the age of 13, serving from 1867 until 1872, and again from 1880 to 1892 as the leader of the Marine Band.

During the Spanish–American War (1898), Marines led American forces ashore in the Philippines, Cuba, and Puerto Rico, demonstrating their readiness for deployment. At Guantánamo Bay, Cuba, the Marines seized an advanced naval base that remains in use today. Between 1899 and 1916, the Corps continued its record of vigorous participation in foreign expeditions, including the Philippine–American War, the Boxer Rebellion in China (1899–1901), Panama, the Cuban Pacifications, the Perdicaris Incident in Morocco, Veracruz, Santo Domingo, and the Banana Wars in Haiti and Nicaragua; the experiences gained in counter-insurgency and guerrilla operations during this period were consolidated into the Small Wars Manual.

United States Marine Corps History in World War I

During World War I veteran Marines served a central role in the late American entry into the conflict. Unlike the Army, the Marine Corps had a deep pool of officers and NCOs with battle experience, and experienced a smaller expansion. Here, the Marines fought their famed battle at Belleau Wood, creating the Marines' reputation in modern history. While its previous expeditionary experiences had not earned it much acclaim in the Western world, the Marines' ferocity and toughness in France earned them the respect of the Germans, who rated them of stormtrooper quality. Though Marines and American media reported that Germans had nicknamed them Teufel Hunden as meaning "Devil Dogs", there is no evidence of this in German records (as Teufelshunde would be the proper German phrase), it was possibly American propaganda. Nevertheless, the name stuck. The Corps had entered the war with 511 officers and 13,214 enlisted personnel, and by 11 November 1918 had reached a strength of 2,400 officers and 70,000 men.

Between the World Wars, the Marine Corps was headed by Commandant John A. Lejeune, and under his leadership, the Corps presciently studied and developed amphibious techniques that would be of great use in World War II. Many officers, including Lt. Col. Earl Hancock "Pete" Ellis, foresaw a war in the Pacific with Japan and took preparations for such a conflict. Through 1941, as the prospect of war grew, the Corps pushed urgently for joint amphibious exercises and acquired amphibious equipment that would prove of great use in the upcoming conflict.

United States Marine Corps History in World War II

In World War II, the Marines played a central role in the Pacific War. The battles of Guadalcanal, Bougainville, Tarawa, Guam, Tinian, Saipan, Peleliu, Iwo Jima, and Okinawa saw fierce fighting between Marines and the Imperial Japanese Army.

Philip Johnston proposed the use of Navajo as a code language to the Corps. The idea was accepted, and the Navajo code was formally developed and modeled on the Joint Army/Navy Phonetic Alphabet.

During the battle of Iwo Jima, photographer Joe Rosenthal took the famous photograph Raising the Flag on Iwo Jima of five Marines and one Navy Corpsman raising the American flag on Mt. Suribachi. Secretary of the Navy James Forrestal, having come ashore earlier that day, said of the flag-raising, "...the raising of that flag on Suribachi means a Marine Corps for the next five hundred years." The acts of the Marines during the war added to their already significant popular reputation. By war's end, the Corps expanded from two brigades to six divisions, five air wings, and supporting troops, totaling about 485,000 Marines. In addition, 20 defense battalions and a parachute battalion were set raised. Nearly 87,000 Marines were casualties during World War II (including nearly 20,000 killed), and 82 were awarded the Medal of Honor.

Despite Secretary Forrestal's prediction, the Corps faced an immediate institutional crisis following the war due to the low budget. Army generals pushing for a strengthened and reorganized defense establishment also attempted to fold the Marine mission and assets into the Navy and Army. Drawing on hastily assembled Congressional support, the Marine Corps rebuffed such efforts to dismantle the Corps, resulting in statutory protection of the Marine Corps in the National Security Act of 1947. Shortly afterward, in 1952 the Douglas-Mansfield Bill afforded the Commandant an equal voice with the Joint Chiefs of Staff on matters relating to the Marines and established the structure of three active divisions and air wings that remain today.

United States Marine Corps History in Korean War

The Korean War (1950–1953) saw the hastily formed Provisional Marine Brigade holding the defensive line at the Pusan Perimeter. To execute a flanking maneuver, General Douglas MacArthur called on Marine air and ground forces to make an amphibious landing at Inchon. The successful landing resulted in the collapse of North Korean lines and the pursuit of North Korean forces north near the Yalu River until the entrance of the People's Republic of China into the war. Chinese troops surrounded, surprised and overwhelmed the overextended and outnumbered American forces. X Corps, which included the 1st Marine Division and the Army's 7th Infantry Division, regrouped and inflicted heavy casualties during their fighting withdrawal to the coast, now known as the Battle of Chosin Reservoir. Marines would continue a battle of attrition around the 38th Parallel until the 1953 armistice. The Korean War saw the Corps expand from 75,000 regulars to a force of 261,000 Marines, mostly reservists. 30,544 Marines were killed or wounded during the war and 42 were awarded the Medal of Honor.

United States Marine Corps History in Vietnam War

The Marine Corps served an important role in the Vietnam War taking part in such battles as Da Nang, Hue City, Con Thien and Khe Sanh. Individuals from the USMC operated in the Northern I Corps Regions of South Vietnam. While there, they were constantly engaged in a guerrilla war against the National Front for the Liberation of South Vietnam (NLF) and an intermittent conventional war against the North Vietnamese Army (NVA). Portions of the Corps were responsible for the less-known Combined Action Program (CAP) that implemented unconventional techniques for counter-insurgency and worked as military advisors to the Republic of Vietnam Marine Corps. Marines were withdrawn in 1971, and returned briefly in 1975 to evacuate Saigon and attempt a rescue of the crew of the Mayagüez.

Vietnam was the longest war for Marines; by its end, 13,091 had been killed in action, 51,392 had been wounded, and 57 Medals of Honor had been awarded. Due to policies concerning rotation, more Marines were deployed for service during Vietnam than World War II.

While recovering from Vietnam, the Corps hit a detrimental low point in its service history caused by courts-martial and Non-Judicial Punishments related partially to increased Unauthorized Absences and Desertions during the war. Overhauling of the Corps began in the late 1970s, discharging the most delinquent, and once quality of new recruits improved, the Corps focused on reforming the NCO Corps, a vital functioning part of its forces.

Interim: Vietnam to the War on Terror

After Vietnam, the Marines resumed their expeditionary role, participating in the 1980 Iran hostage rescue attempt Operation Eagle Claw, the invasion of Grenada (Operation Urgent Fury) and the invasion of Panama (Operation Just Cause). On 23 October 1983, the Marine headquarters building in Beirut, Lebanon, was bombed, causing the highest peacetime losses to the Corps in its history (220 Marines and 21 other service members of the 24th Marine Amphibious Unit were killed) and leading to the American withdrawal from the country. The year of 1990 saw Marines of the Joint Task Force Sharp Edge save thousands of lives by evacuating British, French and American nationals from the violence of the Liberian Civil War. During the Persian Gulf War (1990–1991), Marine task forces formed the initial core for Operation Desert Shield, while United States and Coalition troops mobilized, and later liberated Kuwait in Operation Desert Storm. Marines participated in combat operations in Somalia (1992–1995) during Operations Restore Hope, Restore Hope II, and United Shield to provide humanitarian relief.

United States Marine Corps History in Global War on Terrorism

Following the 11 September 2001 attacks President George W. Bush announced the War on Terrorism. The stated objective of the Global War on Terror is "the defeat of Al-Qaeda, other terrorist groups and any nation that supports or harbors terrorists." Since then, the Marine Corps, alongside other military and federal agencies, has engaged in global operations around the world in support of that mission.

In spring 2009, President Barack Obama's goal of reducing spending in the Defense Department was led by Secretary Robert Gates in a series of budget cuts which didn't result in significant changes in the Corps' budget and programs, cutting only the VH-71 Kestrel and resetting the VXX program. However, the National Commission on Fiscal Responsibility and Reform singled the Corps out for the brunt of a series of recommended cuts in late 2010.

Operation Enduring Freedom

Marines and other American forces began staging in Pakistan and Uzbekistan on the border of Afghanistan as early as October 2001 in preparation for Operation Enduring Freedom. The 15th and 26th Marine Expeditionary Units were the first conventional forces into Afghanistan in support of Operation Enduring Freedom in November 2001, and in December, the Marines seized Kandahar International Airport. Since then, Marine battalions and squadrons have been rotating through, engaging Taliban and Al-Qaeda forces. Marines of the 24th Marine Expeditionary Unit flooded into the Taliban-held town of Garmsir on April 29, 2008, in Helmand province, in the first major American operation in the region in years. In June 2009, 7,000 Marines with the 2nd Marine Expeditionary Brigade deployed to Afghanistan in an effort to improve security, and began Operation Strike of the Sword the next month.

In 2002, Combined Joint Task Force – Horn of Africa was stood up at Camp Lemonnier, Djibouti to provide regional security. Despite transferring overall command to the Navy in 2006, the Marines continued to operate in the Horn of Africa into 2007.

Operation Iraqi Freedom

Most recently, the Marines have served prominently in the Iraq War. The I Marine Expeditionary Force, along with the Army's 3rd Infantry Division, spearheaded the 2003 invasion of Iraq. The Marines left Iraq in the summer of 2003, but returned for occupation duty in the beginning of 2004. They were given responsibility for the Al Anbar Province, the large desert region to the west of Baghdad. During this occupation, the Marines spearheaded both assaults on the city of Fallujah in April (Operation Vigilant Resolve) and November 2004 (Operation Phantom Fury) and also saw intense fighting in such places as Ramadi, Al-Qa'im and Hīt. Their time in Iraq has also courted controversy with the Haditha killings and the Hamdania incident. The Anbar Awakening and 2007 surge reduced levels of violence. On March 1, 2009, President Obama announced an accelerated withdrawal at Camp Lejeune, promising all troops out by August 2010. The Marine Corps officially ended its role in Iraq on January 23, 2010 when they handed over responsibility for Al Anbar Province to the United States Army.

Two small manuals published during the 1930s would establish US Marine Corps doctrine in two areas. The Small Wars Manual laid the framework for Marine counter-insurgency operations from Vietnam to Iraq and Afghanistan while the Tentative Landing Operations Manual established the doctrine for the amphibious operations of World War II. "Operational Maneuver from the Sea" is the current doctrine of power projection.

Capabilities of US Marine Corps: The Marine Corps fulfills a vital role in national security as an amphibious, expeditionary, air-ground combined arms task force, capable of forcible entry from the air, land, and sea. It is capable of asymmetric warfare with conventional, irregular, and hybrid forces.

While the Marine Corps does not employ any unique combat arms, as a force it has the unique ability to rapidly deploy a combined-arms task force to almost anywhere in the world within days. The basic structure for all deployed units is a Marine Air-Ground Task Force (MAGTF) that integrates a ground combat element, an aviation combat element and a logistics combat element combat component under a common command element. While the creation of joint commands under the Goldwater–Nichols Act has improved inter-service coordination between each branch, the Corps' ability to permanently maintain integrated multi-element task forces under a single command provides a smoother implementation of combined-arms warfare principles.

The close integration of disparate Marine units stems from an organizational culture centered around the infantry. Every other Marine capability exists to support the infantry. Unlike some Western militaries, the Corps remained conservative against theories proclaiming the ability of new weapons to win wars independently. For example, Marine aviation has always been focused on close air support and has remained largely uninfluenced by air power theories proclaiming that strategic bombing can single-handedly win wars.

This focus on the infantry is matched with the doctrine that "Every Marine is a rifleman", a focus of Commandant Alfred M. Gray, Jr., emphasizing the infantry combat abilities of every Marine. All Marines, regardless of military specialization, receive training as a rifleman; and all officers receive additional training as infantry platoon commanders. Marines have demonstrated the value of this culture many times throughout history. For example, at Wake Island, when all of the Marine aircraft were shot down, pilots continued the fight as ground officers, leading supply clerks and cooks in a final defensive effort. As a result, a large degree of initiative and autonomy is expected of junior Marines, particularly the NCOs (corporals and sergeants), as compared with many other military organizations. The Marine Corps emphasizes authority and responsibility downward to a greater degree than the other military services. Flexibility of execution is implemented via an emphasis on "commander's intent" as a guiding principle for carrying out orders; specifying the end state but leaving open the method of execution.

The amphibious assault techniques developed for World War II evolved, with the addition of air assault and maneuver warfare doctrine, into the current "Operational Maneuver from the Sea" doctrine of power projection from the seas. The Marines are credited with the development of helicopter insertion doctrine and were the earliest in the American military to widely adopt maneuver-warfare principles which emphasize low-level initiative and flexible execution. In light of recent warfare that has strayed from the Corp's traditional missions, it has renewed an emphasis on amphibious capabilities.

The Marine Corps relies on the Navy for sealift to provide its rapid deployment capabilities. In addition to basing a third of the Fleet Marine Force in Japan, Marine Expeditionary Units (MEU) are typically stationed at sea. This allows the ability to function as first responders to international incidents. The United States Army now maintains light infantry units capable of rapid worldwide deployment, but those units do not match the combined-arms integration of a MAGTF and lack the logistics that the Navy provides. For this reason, the Marine Corps is often assigned to non-combat missions such as the evacuation of Americans from unstable countries and providing humanitarian relief during natural disasters. In larger conflicts, Marines act as a stopgap, to get into and hold an area until larger units can be mobilized. The Corps performed this role in World War I and the Korean War, where Marines were the first significant combat units deployed from the United States and held the line until the country could mobilize for war. To aid rapid deployment, the Maritime Pre-Positioning System was developed: fleets of container ships are positioned throughout the world with enough equipment and supplies for a Marine Expeditionary Force to deploy for 30 days.

The Marine Corps was founded to serve as an infantry unit aboard naval vessels and was responsible for the security of the ship and its crew by conducting offensive and defensive combat during boarding actions and defending the ship's officers from mutiny; to the latter end, their quarters on ship were often strategically positioned between the officers' quarters and the rest of the vessel. Continental Marines also manned raiding parties, both at sea and ashore. America's first amphibious assault landing occurred early in the Revolutionary War as the Marines gained control of a British ammunition depot and naval port in New Providence, the Bahamas. The role of the Marine Corps has since expanded significantly; as the importance of its original naval mission declined with changing naval warfare doctrine and the professionalization of the Naval service, the corps adapted by focusing on what were formerly secondary missions ashore. The Advanced Base Doctrine of the early 20th century codified their combat duties ashore, outlining the use of Marines in the seizure of bases and other duties on land to support naval campaigns.

Throughout the late 19th and 20th centuries, Marine detachments served aboard Navy cruisers, battleships and carriers. Marine detachments (generally one platoon per cruiser, a company for battleships or carriers) served their traditional duties as ship's landing force, manning the ship's weapons and providing shipboard security. Marine detachments were also augmented by members of the ship's company for landing parties, especially in the Caribbean and Mexico campaigns of the early 20th centuries. Marines would also develop tactics and techniques of amphibious assault on defended coastlines in time for use in World War II. During World War II, Marines continued to serve on capital ships. They often were assigned to man anti-aircraft batteries. When gun cruisers were retired by the 1960s, the remaining Marine detachments were only seen on battleships and carriers. Its original mission of providing shipboard security finally ended in the 1990s when nuclear weapons were withdrawn from active deployment and the battleships were retired.

US Marine Corps Mission: The United States Marine Corps serves as an amphibious force-in-readiness. As outlined in 10 U.S.C. § 5063 and as originally introduced under the National Security Act of 1947, it has three primary areas of responsibility:

• The seizure or defense of advanced naval bases and other land operations to support naval campaigns;
• The development of tactics, technique, and equipment used by amphibious landing forces; and
• Such other duties as the President may direct.

This last clause, while seemingly redundant given the president's position as Commander-in-chief, is a codification of the expeditionary duties of the Marine Corps. It derives from similar language in the Congressional acts "For the Better Organization of the Marine Corps" of 1834, and "Establishing and Organizing a Marine Corps" of 1798. In 1951, the House of Representatives' Armed Services Committee called the clause "one of the most important statutory — and traditional — functions of the Marine Corps." It noted that the corps has more often than not performed actions of a non-naval nature, including its famous actions in the War of 1812, at Tripoli, Chapultepec, numerous counter-insurgency and occupational duties (such as those in Central America), World War I, and the Korean War. While these actions are not accurately described as support of naval campaigns nor as amphibious warfare, their common thread is that they are of an expeditionary nature, using the mobility of the Navy to provide timely intervention in foreign affairs on behalf of American interests.

In addition to its primary duties, the Marine Corps has missions in direct support of the White House and the State Department. The Marine Band, dubbed the "President's Own" by Thomas Jefferson, provides music for state functions at the White House. Marines guard presidential retreats, including Camp David, and the Marines of the Executive Flight Detachment of HMX-1 provide helicopter transport to the President and Vice President, using the call signs "Marine One" and "Marine Two" respectively.

By authority of the 1946 Foreign Service Act, the Marine security guards of the Marine Embassy Security Command provide security for American embassies, legations, and consulates at more than 140 posts worldwide.