“Often the armed guard went out alone, and finally the Colonization Group got shortened to UNEF, United Nations Exploratory Force. Emphasis on the ‘force.’” 

Human exploration of space on the other side of the collapsars quickly shifts to colonization, and then, after a Tauran attack, the military role takes priority as the conflict escalates. As a veteran of the Vietnam War, Haldeman witnessed firsthand how colonization (the French in Indochina) can easily lead to war (the American presence in Vietnam and its bombing of Laos and Cambodia). War presupposes a natural right to a given territory, and rather than assume they have encroached upon Tauran space, the humans stake out a claim and back it up with force. 

“The suit was fairly comfortable, but it gave you the odd feeling of simultaneously being a marionette and puppeteer.” 

Mandella and his platoon practice maneuvering in their armored suits for the first time on Charon. The suits both manipulate the wearer and give them control, an apt metaphor for a military life. Soldiers of a certain rank—sergeant, captain, major—have a degree of autonomy, particularly in the far reaches of outer space, including the to kill as they see fit. On Mandella’s first mission, his platoon slaughters a herd of creatures they call “teddy bears” for no other reason than they look strange. At the same time, the bureaucracy controls nearly every aspect of the soldiers’ life: their assignment, the duration of their enlistment, even their recovery time after an injury.