Too RINO for the Republicans, too DINO for the Dems? It’s a longshot — Specter leads him by 40 points thanks to the advantage in name recognition — but this’ll at least make him squirm a little on his way to the nomination. It helps Toomey, too, since Sestak supports card check and will run to Specter’s left; the more Benedict Arlen attacks him from the center, the more likely disgruntled lefties and union members will hold a grudge during the general election.

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.”…

Earlier today, a Sestak volunteer and contributor received a handwritten note from Sestak himself, announcing his intent to run and asking for a contribution.

Ed thought this was a no-brainer a few weeks ago but I’m really surprised given The One’s pledge to support Specter when he switched parties. In fact, they’re appearing together at a fundraiser in L.A. tonight. I don’t know how Sestak expects to overcome the incumbency advantage and the opposition of a popular president, unless he’s been misled by the nutroots into thinking they’re much more of a fundraising powerhouse than they actually are. Per the Standard, dKos is already sending around a virtual collection plate on his behalf. If you know any progressives with cash to spare, do forward the link, please.

Update: Just arrived in my inbox, a statement from Toomey HQ. Let us unite with our liberal brothers in mutual hatred of Specter!

“While Joe Sestak and I disagree on a host of issues,” Mr. Toomey said, “I commend him for being a principled liberal who stands up for his beliefs and values. I have always believed that Pennsylvania voters—not party bosses in Washington—should have the final say over whom their nominees will be.”

“There would be no lack of substantive policy differences in a general election race between Pat Toomey and Joe Sestak, but Pennsylvanians would get the kind of refreshing campaign they deserve—honest and straightforward, without the distortions and mudslinging that characterize Arlen Specter’s tired old approach to politics,” added Toomey Communications Director Nachama Soloveichik. “If you want to see what kind of campaign Senator Specter will run, just look at the first ad he ran this year—an ad he was forced to remove from the airwaves because it contained blatantly false attacks on Pat Toomey. Pennsylvania Democrats are just as likely to reject Arlen Specter’s politics of expediency as Pennsylvania Republicans did.”