<P> Since World War II in many crises the United States Marine Corps has deployed projection forces, with the ability to move ashore with sufficient sustainability for prolonged operations . MAGTFs have long provided the United States with a broad spectrum of response options when U.S. and allied interests have been threatened and in non-combat situations which require critical response . Selective, timely and credible commitment of air - ground units has, on many occasions, helped bring stability to a region and sent signals worldwide that the United States is willing to defend its interests, and is able to do so with a powerful force on short notice . </P> <P> The four core elements of a Marine air--ground task force are: </P> <Ul> <Li> The command element (CE), a headquarters unit organized into a MAGTF (MEU, MEB, MEF) headquarters (HQ) group, that exercises command and control (management and planning for manpower, intelligence, operations and training, and logistics functions) over the other elements of the MAGTF . The HQ group consists of communications, intelligence, surveillance, and law enforcement (i.e., military police) detachments, companies, and battalions, and reconnaissance (Force Reconnaissance), and liaison (ANGLICO) platoons, detachments, and companies . </Li> <Li> The ground combat element (GCE), composed primarily of infantry units (infantry battalions organized into battalion landing teams, regimental combat teams, and Marine divisions). These organizations contain a headquarters unit that provides command and control (management and planning for manpower, intelligence, operations and training, and logistics functions) as well as scout / sniper, aviation liaison / forward air controller, NBC defense, communications, service (supply, motor transport, weapons maintenance, and dining facility), and Navy combat medical and chaplain's corps personnel . The GCE also contains combat support units, including artillery, armor (tank, assault amphibian, and light armored reconnaissance), combat engineer (including EOD), and reconnaissance units . At the division level, the GCE also contains limited organic combat service support, including a truck company, a military police / law enforcement company, and the division band . </Li> <Li> The aviation combat element (ACE), which contributes the air power to the MAGTF includes all aircraft (fixed wing, helicopters, tiltrotor, and UAV) and aviation support units . The units are organized into detachments, squadrons, groups, and wings, except for low altitude air defense units, which are organized into platoons, detachments, batteries, and battalions . These units include pilots, flight officers, enlisted aircrewmen, aviation logistics (aircraft maintenance, aviation electronics, aviation ordnance, and aviation supply) and Navy aviation medical and chaplain's corps personnel, as well as ground - based air defense units, and those units necessary for command and control (management and planning for manpower, intelligence, operations and training, and logistics functions), aviation command and control (tactical air command, air defense control, air support control, and air traffic control), communications, and aviation ground support (e.g., airfield services, bulk fuels / aircraft refueling, crash rescue, engineer construction and utilities support, EOD, motor transport, ground equipment supply and maintenance, local security / law enforcement, and the wing band). </Li> <Li> The logistics combat element (LCE), organized into battalions, regiments, and groups, has its own headquarters element for command and control (management and planning for manpower, intelligence, operations and training, and logistics functions) of its subordinate units and contains the majority of the combat service support units for the MAGTF, including: heavy motor transport, ground supply, heavy engineer support, ground equipment maintenance, and advanced medical and dental units, along with certain specialized groups such as air delivery, EOD, and landing support teams . </Li> </Ul> <Li> The command element (CE), a headquarters unit organized into a MAGTF (MEU, MEB, MEF) headquarters (HQ) group, that exercises command and control (management and planning for manpower, intelligence, operations and training, and logistics functions) over the other elements of the MAGTF . The HQ group consists of communications, intelligence, surveillance, and law enforcement (i.e., military police) detachments, companies, and battalions, and reconnaissance (Force Reconnaissance), and liaison (ANGLICO) platoons, detachments, and companies . </Li>

What is the core element of the marine air ground task force
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