US Marines

The United States Marine Corps was one of five branches of the United States Armed Forces. Closely cooperating with the United States Navy for mobility, the Marine Corps acted as the United States force in readiness. In the 21st century, the Marine Corps would spearhead assaults into the Chinese mainland in 2074. Despite claims of fighting a defensive war, American infantry and mechanized divisions landed in Asia, in a counter-invasion of Chinese mainland. In the Yangtze Campaign, U.S. Marines rapidly overran Shanghai and Nanjing, securing a major port for bringing in troops and materiel.

On the domestic front, the Marine Corps would be responsible for protecting Navy facilities, especially black sites such as Sugar Grove in Appalachia, the Mount Desert Island Naval Facility at Mount Desert Island, participating in war games with other military assets, such as United States Army Rangers, and rounding up civilians for internment in accordance with Executive Order 99066. Due to a shortage of manpower, the USMC would hand these contracts to private military contractors.

Although the United States of America and all of its military branches ceased to exist during the Great War, elements of the Marine Corps seem to have survived in the Enclave, of all places, where the values integral to the Corps were instilled into its servicemen. Frank Horrigan is a noticeable example.

Technology
The United States Marine Corps used many of the same weapons as the United States Army, but would use a number of tools unique to the branch, including the riot gear customized for desert operations and Wattz 2000 laser rifles for its sharpshooters. Marine Corp detachments embedded with Navy warships and posted to Navy facilities also used heavy suits of combat armor and specialized infiltration gear in their operations.