UPDATED: Report: Sestak to challenge Specter in 2010

It's on!

Rep. Joe Sestak (D-PA) is privately telling supporters that he intends to run for Senate, TPMDC has confirmed.

"He intends to get in the race," says Meg Infantino, the Congressman's sister, who works at Sestak for Congress. "In the not too distant future, he will sit down with his wife and daughter to make the final decision."

The move would constitute a primary challenge to Sen. Arlen Specter (D-PA), who intends to run for re-election in 2010, after having switched parties earlier this year.

Earlier today, a Sestak volunteer and contributor received a handwritten note from Sestak himself, announcing his intent to run and asking for a contribution. The source provided TPMDC a scan of the letter:

You can see the whole letter here.

I have some thoughts on Sestak's apparent candidacy that I'll share tonight.

UPDATE: OK, not so much here, as I was tied up on the faux kidnapping saga all night here in the newsroom. The point was that a Sestak candidacy is a win-win kind of deal for Sestak and the Democratic Party. For the Dems,  Sestak will either push Arlen to the mainstream of the Democratic Party (i.e., further left of wherever he's at now) and then gets out, or Arlen votes too often with the R's, and the party will be happy to see Sestak stay in. For Sestak, if it works out under Scenario 2, then he's the junior senator from Pa. (I mean, Pat Toomey, come on...) or under Scenario 2, the party leaders move him to the head of the line when one of the state's two slots becomes open, or he gets a good job in the Obama administration.

Or maybe we'll get the most liberal candidate of the entire lot to change his mind...Tom Ridge. I'm beginning to really like that guy. :-)