WP: ad is make or break moment

Over at the WashPost, Chris Cillizza -- always a Sestak believer -- calls the congressman's long-awaited ad on Specter's Republican past "the make or break moment of the Pennsylvania primary":

While the Bush footage is damaging -- reminding Democratic voters of their wariness about casting a vote for someone with such a long history in the Republican party -- it's Specter's own words that may be the toughest part of the ad.

"My change in party will enable me to be re-elected," Specter is shown saying twice in the 30-second ad. The commercial's narrator adds: "Arlen Specter changed parties to save one job....his, not yours."

. . . In an era where voters have grave misgivings about Washington generally and politicians specifically, Specter's seemingly self-serving justification for the switch -- and the fact that it comes directly from him in the ad -- means that there is real danger in the next few days for the Senator.

Make no mistake: this ad is the make or break moment of the Pennsylvania primary. This is the ad that Sestak saw in his mind's eye when he decided to run against Specter despite the fact that the entire establishment -- including President Barack Obama -- had lined up behind his opponent.

With polling suggesting that he is down by mid to high single digits, Sestak is laying it all on the line with this ad. Watch to see if numbers move in a significant way over the next week as the ad reaches saturation level. If Specter can weather this ad, he will win. If not, the race will be Sestak's for the taking.

UPDATE: Over at OpenLeft, Sestak supporter (and state Dem committeeman) Chris Bowers calls the ad "devastating" and says when paired with low turnout May 18 puts Specter in a heap of trouble.