Bob Menendez, as The Opinion Mill points out, voted against the war and has remained against the war ever since.
Jim Tester was critical of the war and appears to have defeated Conrad Burns in Montana.
Sheldon Whitehouse opposed the war and while his opponent, the incumbent Republican Lincoln Chafee, is rather independent, that big fat R on his chest and the party’s responsibility for the war was the “decider” here.
I could go on, but it might be better to just read this from John Nichols.
South Brunswick Post, The Cranbury Press
The Blog of South Brunswick