He voted for the war after being misled about it, like all Americans, by Bush.
Not because of intelligence, but because when Bush asked to be given the power to go to war, he promised he had a plan, that he'll go to war as a last resort and that he'll build a strong coallition, none of which he did.
Plus he never said he'd pull the troops out of Iraq on his first day as President, he said he'd bring more strong allies back to the table to be more efficient on the ground and build a strong and safe plan, that doesn't exist today with Bush, for the reconstruction of Iraq.
If things went along like in his plan, the troops would still be in Iraq for at least four years.

Ponrauil