Last night I mentioned that I would like to see a poll other than the Muhlenberg tracking poll confirm the surge of Joe Sestak in the Pennsylvania Democratic primary for US Senate. The tracking poll shows Sestak with a 5-point lead now. And so does Rasmussen, by the same numbers: 47% Sestak, 42% Specter, with 11% undecided.

I’d feel better about this if it was a polling outfit other than Rasmussen. However, the trend line definitely shows Sestak moving:

Specter’s support has slipped from 48% in March to 44% a month ago to 42% today.

The numbers for Sestak have been going in the opposite direction from 37% in March to 42% a month ago to 47% today.

What’s brilliant is that, despite Sestak’s brutal ad showing Specter as a clone of George Bush and Sarah Palin, Specter is the one seen as running a negative campaign. Sestak’s strategy has been nothing short of brilliant – he started positive, waited for Snarlin’ Arlen to attack him, made sure everyone knew it, and attacked right back.

Many have noticed that Specter voted against Elena Kagan’s nomination for Solicitor General last year, when he was trying to impress the arch-conservatives. This could certainly cause a headache for Specter in the final days of the race, especially in the midst of a conversation of whether Specter is a loyal Democrat. Expect him to come out immediately saying he has changed his mind, which won’t help him either.

UPDATE: Chris Bowers adds that Sestak is probably more electable than Specter too, and this is one of Specter’s last effective arguments.

UPDATE II: Sestak puts Specter in an impossible position on the Kagan nomination:

“My opponent, Senator Specter, has already made his views about the President’s nominee clear by voting against her confirmation to be Solicitor General, even as seven of his fellow Republicans approved her nomination. I expect Senator Specter may backtrack from his earlier vote on Ms. Kagan this week in order to help himself in the upcoming primary election, but the people of Pennsylvania have no way of knowing where he will stand after May 18.”

If Specter continues his opposition, he isn’t a “team player” Democrat. If he flips, he furthers his reputation as a flipper. About the only way Specter gets out of this is by making a principled case against Kagan on executive power or civil liberties grounds, but that would be out of character.