Slacktivist has the best take
I've read on the psychology behind the recent "McCain doctrine" push for troop escalation in Iraq:
The call for a "troop surge" in Iraq is also the first step in the creation of our next myth -- the one that explains why we lost this war. No matter how many additional troops are included in this "surge" it will be judged, by the mythmakers, as not more enough. And Congress, or the press, or the public, can later be blamed for not doing "more" -- for not allowing us to do what needed to be done to win.
The "more" of course being more atrocities and oppression, but this usually isn't spelled out by the advocates of "more".