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PA: On to the campaign...

From NBC's Domenico Montanaro
Specter challenger Pat Toomey, former president of the Club for Growth, told NBC's Andrea Mitchell on MSNBC that Specter's switch is "very unfortunate," but not "surprising."

He charged that Specter shared "a liberal or left-of-center ideology" with Democrats in the Senate, and now his party identification matches his ideology.

Toomey upped the rhetoric, setting up a likely campaign mantra: "Can they trust this man?" Toomey said of what the question Pennsylvanians should ask themselves about Specter.

He added, that "just last week, he went around Pennsylvania" saying that we "can't turn control of the government" over to the Democrats. "He has to answer to that," Toomey said.

Mitchell asked, however, about Toomey and others in the party apparently trying to cast Specter as a left-winger. (RNC Chairman Michael Steele's, for example, noted in his statement that Specter left "because he knew that he was going to lose a Republican primary due to his left-wing voting record.")

She asked, isn't Specter more of a moderate and hasn't the Republican party in Pennsylvania gotten more conservative?

"I don't think the Republican Party has changed in Pennsylvania," Toomey said, adding that Specter is trying to be on "both sides" of every issue. He cited "card check" in particular.

"I think voters are fed up with people who are only concerned about their political fortunes and don't stick to principles or ideas."

Of note, Republicans have gone into full oppo mode against Specter, passing around background research:

Q: "Some Democrats have approached you to switch, why not take them up on it?" SEN. ARLEN SPECTER (R-PA): How do you know that as a fact just because Rendell and Biden said that publicly? Q: "Sure, why not take the path of the least resistance." SEN. ARLEN SPECTER (R-PA): "Because I am a Republican." ("Arlen Specter Unfiltered," Pennsylvania Avenue, 4/16/09)

SEN. ARLEN SPECTER (R-PA): "I'm staying a Republican because I think I have a more important role to play there." ("Specter won't rule out run as an Independent," The Hill, 3/17/09)

SEN. ARLEN SPECTER (R-PA):  'I think each of the 41 Republican senators, in a sense — and I don't want to overstate this — is a national asset,' he said, 'because if one was gone, you'd only have 40, the Democrats would have 60, and they would control all of the mechanisms of government.'" ("Specter Won't Rule Out Run As An Independent," The Hill, 3/17/09)

SEN. ARLEN SPECTER (R-PA): "And because if we lose my seat they have 60 Democrats, they will pass card check, you will have the Obama tax increases, they will carry out his big spending plans. So the 41st Republican, whose name is Arlen Specter is vital to stopping tax increases, passage of card check, and the Obama big spending plans." ("Arlen Specter Unfiltered," Pennsylvania Avenue, 4/16/09)

SEN. ARLEN SPECTER (R-PA): "All that is standing between the Democrats and an avalanche are the 41 Republican Senators to to filibuster. If hes [Toomey] the nominee we lose the seat and you have card check, and you have tax increases and you have all of the big Obama spending programs." ("Arlen Specter Unfiltered," Pennsylvania Avenue, 4/16/09)