For example, my SIL, who, as of mid-March, was for the war because it'd be good for Israel and "good for women" (yes, I KNOW that the status of women in Iraq is miles above what it is in Saudi Arabia, Iran, etc.)
I honestly think much of this is psychological in origin and has to do with some of those old "cognitive-dissonance" and "value-congruence" things that we learned about in college Psych and Social Psych, like about how if you have a tough decision to make about buying a car, then after you do it you talk yourself into believing that you made the right decision, it's the best possible car, etc.
If you believe that the US is making an unjustified war, then (a) it's horrible, (b) you don't think you can do anything about it, (c) you have to be in conflict with the media, respected people, and so on, (d) you have to be ambivalent about 'supporting the troops', you think maybe they died for nothing, etc., (e) you have to believe that the president is lying to you, (f) you have to believe that the system is so screwed up that something like this can happen, and so on. This is all pretty depressing. Hell, it depresses ME.
But if you can come up with some kind of reason why you think the war is ok, then all of these sources of mental distress dry up and you can go around on a cloud of triumphant cheer. So you can believe something that will make you miserable, or you can believe something that will make you happy and proud. Which are you gonna do?
LP