Rudy Giuliani's been pretty late to the online video game, and he's been reluctant to use the web for anything that smells of voter engagement. But he's slowly learning, as is evidenced by staffer Dan Meyers' Running with Rudy video series, Rudy's fancy Facebook page, and the MySpace page he recently made public. Now he's produced his first video ad, and it's pretty good.

Titled "She Changed," it's all about Hillary.

Hillary supported the war, and then she didn't, the ad tells us. And worst of all, she teamed up with the "radical group" MoveOn.org to attack General Petraeus in a "venomous ad" in the New York Times. How could she? the ad implies. "Just when the troops need all our support to finish the job, Hillary Clinton is turning her back on them."

The video signals a turning point in the campaign; a Republican front-runner is now attacking a Democratic front-runner while still having to fight for the nomination. As an attack ad goes, it's good. And regardless of the merit of its Times ad, MoveOn.org has given both sides an excuse to hit hard, adding some serious drama to the campaign.