I've never really trusted politicians period, regardles of nationality or political party. I see politicians as opprtunists who tell people what they want to hear, or give them someone to blame, and are either unable or unwilling to follow up on it. This is one bias or stereotype I readily admit to, and I'm not ashamed of it. Which is sad, because after all the phonies out there, it makes me unwilling to put my trust behind someone who might actually be a decent person.
As for the military, I have a lot of respect for our armed forces. They have a tough job to do, and often go unappreciated. It's the politicians who direct them that I don't trust, for reasons stated above. I do get annoyed with people who feel that not wanting our troops to be in danger out of concern for their welfare constitutes cowardice and treason. And there have been people who have said this (not here, though - at least not that I recall).
As for whether or not America is an "evil empire" or out to redeem the world, I don't think we're either. We're a nation like any other. We have much to be proud of, and much to be ashamed of, and it's important to remember both. But I have to say, having travelled to 16 different countries in my brief time, I will say that Americans have much to be grateful for.
As for the Iraq question...again, my answer comes from a lack of faith in politicians in general - it was a necessary step, but I can't trust the motivations of the politicans who advocated the war.
(And the people who criticize the UN for trying to avoid war need to realize that one of the main reasons for the UN's existence is to try and prevent war.)