Early militancy was symptomatic of Roman Catholic control of the church (and it's offshoots), wherein the bible was not taught to its subjects, only religiously recited in Latin, which few knew. Meanwhile even protestants had to fight for their lives. Do you know what they did to Tyndale?

This was all pretty far askew from the ideals espoused by Jesus, in fact more the behavior of religious Pharisees, whom Christ sternly rebuked.

Catholicism is now much more broad and well informed, responsible for a lot of good work, and IMHO are becoming less attached to the more heretical teachings, but still quite far from some of Jesus' own admonitions.

Now, if you're referring to Bush putting the US in Iraq, I don't know any Christians that honestly thought that was a good idea. It really didn't follow with 9/11, it seemed to follow Bush Sr. At any rate, they say that the chemical WMDs that had been there ended up in Syria (which fits), so it might not have been completely baseless.

Much of American "oppressive militancy" is on it's face the attempt (perhaps wrongly) to secure peace and democracy amongst cultures which do not value peace, democracy, or even respect for life. Whatever ulterior motives you assign (and there probably are a few), that is the position and objective which the majority of soldiers adhere to, and many peaceful locals do recognize that their intentions are good, their actions generally necessary to prevent takeover by absolutely ruthless and fanatical factions. A full and proper hand-off of power, however, could take generations. We definitely bit off more than we can chew there, but it seems to me that it was at least as much because of secular world peace idealism as anything else.