One of the worst things Bush did is to discredit military intervention for humanitarian reasons. It will unfortunately take a while for the American left to support it again, even when done by a Democratic president.
I see your point, but respectfully have to disagree with one thing, Lief. You cannot blame Bush for an anti-war sentiment. Those who rally to use military intervention or those who oppose it are probably and were probably sound in their beliefs well before President Bush came into office.
