Well, Americans are a certain mixed bag of opinions, but as I alluded to in another thread, Americans have tended to have a certain "national security" mindset which has existed since WW2 and the onset of the Cold War. Among other things, some of the consequences of that involves people arranging their minds in such a way that it creates a need to defend the government and system while maintaining a certain degree of plausible deniability. I don't think they're really "pretending."
Ironically, Americans aren't exactly strangers to the idea of expansionism by force to gain more land and resources. Americans tended to support policies like that during the 19th and early part of the 20th centuries, continuing on with our forays into China and solidifying our hegemony over Latin America. As long as we knew our limits and didn't interfere in the political order of Europe or their imperial possessions/interests overseas, we were in a fairly safe and advantageous position, geopolitically speaking.
The problems came in when the political order in Europe pretty much self-destructed on its own, by its own devices and its own rules. Somehow, America got dragged into it - and not only in Europe, but throughout the remnants of the European colonial empires which were falling into chaos and vulnerable to communist agitation. Latin America was also vulnerable, so they had to intervene there a few times as well. At home, Americans were led to believe that we were defending the "free world," in some noble cause which had somehow locked us in a death struggle with communism.
Once you get believing in stuff like that, then anything is possible. It can also backfire, as it has on more than one occasion.
Even worse, whoever gets the job of President gets to be in command of the biggest, most devastating war machine ever devised, along with a state-of-the-art electronic surveillance net, and a world-wide intelligence agency with many capabilities - along with various domestic law enforcement agencies.
Oops.
We can only hope that some clinker doesn't get in and wind up in control of all of that.