...Is there a dissonance there, or am I missing something?

Perhaps both.

I think the only meanigful answer to "Do Americans trust their government?" is "Yes and no."

Even Canadian Liberals may disagree with some of Chretien's platform, just as some Republican take issue with Bush. Yet on the other hand, there are Democrats who are highly supportive of Bush.

Do American trust their government? It's too general a question to be meaningful, imo. I think what you got from discussing politics with you friends is not a snapshot of the American psyche, but rather the opinions of two very nice people.

As well, I strongly suspect that a certain dissonance is part of human nature, not just the American character.