Like the Army, the United States Marine Corps (USMC) is modernizing to meet emerging threats. These efforts are most evident in the Marine Expeditionary Units (MEUs).

Marine Expeditionary Units (MEUs) are small and flexible combined-arms units that can act as a theater quick-reaction force. They’re designed around a reinforced battalion, also known as the Battalion Landing Team, which serves as the Ground Element of the MEU. The Aviation Element, which is comprised of helicopters and Short Take-Off and Vertical Landing (STOVL) aircraft, such as the AV-8 Harrier or the F-35B, which provide air support. A logistics combat element and a command element provide ensure operational readiness and leadership.

The USMC has steadily implemented new concepts in the 13th and 31st MEUs, which are seen as examples of how a Marine Corps geared for nation-level wars should look like. For example, during a recent deployment in the Pacific, the 13th MEU fired the High Mobility Artillery Rocket System (HIMARS) from the deck of a ship in order to determine its effectiveness against shore targets. This testing was done with the South China Sea Islands in mind, where China is trying to construct an anti-ship zone to protect its mainland from the danger of the U.S. Navy’s aircraft carriers.

The F-35Bs also allowed for more complex operations that were previously unattainable with the AV-8 Harriers. The advanced sensors of the F-35B were used to rapidly share targeting information across the MEUs support assets and thus, coordinate strikes at a target. During the HIMARS testing, for instance, F-35Bs used sensors to locate and pinpoint targets, and share them with the HIMARS crews, who then launched their missiles.

The biggest change comes in the employment of MEUs. Previously, MEUs would spend their entire deployment in a single area, for example in Afghanistan or Iraq. Now, the strategic shift has MEUs visiting dozens of places in the span of a single deployment.

“It’s not so much the case as going to one place and staying there the whole deployment,” said Captain Gerald Olin, the commander of Amphibious Squadron One, in an interview with the Marine Corps Times. “It’s the ability to operate in any theater at any time. We move our ships around when we want them to be in certain places, so we have them where we want them.”

This development is natural evolution, considering the increasing importance the U.S. Department of Defense places on a potential future conflict with China or Russia.