who are the marines that guard the president
Marine Security Guard A Marine Security Guard (MSG), also known as a Marine Embassy Guard, is a member of the Marine Corps Embassy Security Group[3][4] (formerly Marine Security Guard Battalion), a battalion-sized organization of U.S. Marines whose detachments provide security at American embassies, American consulates and other official United States Government offices such as the United States Mission to NATO in Brussels, Belgium. The Marine Security Guard was designated MOS 8151, this has changed to MOS 8156.