Sen. Arlen Specter (R-Pa.), already running ads for a primary that's more than a year away, appeared on MSNBC's "Morning Joe" today and shed some light on what his main argument will be against Club for Growth president Pat Toomey: electability.

"If Mr. Toomey is the nominee, you can be sure he'll lose," Specter said. "He's to the right of Rick Santorum. Santorum lost by 18 points, spent $31 million and was a two-term incumbent. And if Toomey is the nominee, there will be 60 Democrats. ... If there's a Democrat in my place, they'll be able to do anything they want."

In 2006, Santorum outspent now-Sen. Bob Casey (D) by millions of dollars and still lost by 18 points. Democrats have also picked up five House seats from Pennsylvania since the 2006 election, and President Obama won what was supposed to be a battleground state by 11 points.

Asked whether he is paying for crossing party lines on bills such as the economic stimulus package, Specter said: "I know I am. Mr. Toomey was going to run for governor. When I voted for the stimulus, he saw an opening and has come into the Senate race.

"Had a very tough race with him last time, but it's a different year. It's a different year for him because of his background -- a Wall Street trader; was in the House of Representatives for six years, fought against deregulation... When you take a look at his record, he's been contributive to the problem. And now he wants a promotion; he wants a bonus like those AIG guys."

National Republican Senatorial Committee Chairman John Cornyn (Texas) appeared on "Morning Joe" shortly after Specter and noted the importance of the seat. "Hopefully he and Mr. Toomey don't cut each other up because we're going to need to hold on to Pennsylvania," said Cornyn.