I'm getting some concern trolling on this, so let's say it clearly: That the Democratic senators allowed a vote to condemn the MoveOn ad was the absolute height of spineless cowardice. More than that, it's stupid: They have nothing to gain and everything to lose from such a vote. Those who vote for the resolution will see no political benefit. Those who voted against may suffer some harm. Matt's right to say that Washington liberals were bizarrely outraged over the ad, but it's worth pointing out that those same establishment types think vote was a stupid and inexplicable legislative mistake. My understanding is that the Dems basically got rolled by some members of their conservative flank and some smart parliamentary maneuvering by the Republicans, but it's not terribly clear how that happened.
As a general point, I think MoveOn was right to point out that the Senate moved to this vote directly after failing to pass Webb's legislation to guarantee soldiers as much time at home with their family as they spent deployed in Iraq. It's shameful stuff.