ALIENS: Colonial Marines Technical Manual

From the introduction: THE UNITED STATES COLONIAL MARINES (USCM) The 'United States Colonial Marine Corps is America's interstellar force-in-readiness. This role, distinct from that of the US Army, stems from the country's position as a starfaring, colonising power, and its leading role within the structure of the United Americas. Though the term "Marine" has its roots in describing a soldier who fought from ships at sea, in the modern era it has become synonymous with those elite forces of soldiers who are always read to fight, regardless of their nation's readiness for war, and who are capable of operating far from home soil. The Colonial Marine Corps has a dual responsibility. First, to serve on land, on sea, in air and in space; second, to exploit the advantages of readiness and interstellar deployment capability.