*buries worms quietly back in soil*
A few points.
1. FWIW, I also didn't like Catcher in the Rye all that much when I read it in high school. Have you read The Chocolate War (Cormier)? The Forever War (Haldeman)? A Separate Peace (Knowles)? You might like those more. I'll pm you my thoughts on enlistment.
2. I was suspicious of the SS as well, since I figured this game would attract some far right-types. Instead, I've met more centrist to liberals than reactionaries. If Vicious says he doesn't support the SS, I believe him until he proves otherwise. I haven't talked with him much, but have yet to see anything like that come out of his mouth. It could just as easily refer to SS missiles. Or maybe he dreams of driving an Impala when he starts driving.
3. The oath does have that language, but it's more symbolic than a warrant for action. The warrant is given legislatively: the military's role in the domestic sphere is governed by the Posse Comitatus Act (1878) and the Insurrection Act (1807). There are some rare cases where the military can be mobilized against domestic threats. Military force was used frequently in labor disputes in the late 19th and early 20th century. The Bonus Army of poor veterans were dispersed from Washington, D.C. in 1932 by infantry and a few tanks under MacArthur and Patton (Posse Comit. doesn't apply to D.C.). Eisenhower federalized the national guard and deployed 101st Airborne troops in Little Rock to escort children to school and enforce the 14th Amendment in 1957. National guard and federal troops were sent into Chicago to quell the rioting after Martin Luther King's death. And of course, many of us are familiar with the fighters patrolling above our cities after September 11.
Defense authorization bills in 2006 and 2007 made it a lot easier to deploy the military in domestic law enforcement roles, but these expanded powers were repealed (as they should have been) in 2008.
The Siege, though melodramatic, was built around the tension of the role of military and civil policing in American democracy. 24 also plays with this theme a lot, usually in a one-sided and reductive way.
If any of you have access to JSTOR, there's an article (which I have yet to read) by David Adams in the Journal of Peace Research, v. 32 (May 1995): 197-211 titled "Internal Military Intervention in the United States."
http://www.jstor.org/stable/425067