Below The Beltway

Once again, Arlen Specter will be facing a challenge from the right when he runs for re-election in 2010:

Former Rep. Pat Toomey (R-Pa.) will challenge Sen. Arlen Specter in a primary for the second straight cycle, according to Pennsylvania GOP sources.

The Allentown Morning Call reported Thursday that two friends of Toomey’s have said the Club for Growth chief has decided to enter the race.

Toomey narrowly lost to Specter in a 2004 primary by less than 1 percent and recently said he was considering another run.

The paper quotes Richard Thulin, leader of the Lehigh Valley Republican Network, saying in an e-mail to supporters that “Pat’s formal announcement will be forthcoming.

And, this time, it appears that Specter’s best chance of staying in office is to leave the Republican Party

Sen. Arlen Specter (R-Pa.) does not have the fall-back option of running as an independent should he lose his 2010 primary election, giving the senior lawmaker strong incentive to abandon his party this year.

Specter faces an extremely difficult primary race against former Rep. Pat Toomey (R-Pa.), the conservative firebrand who lost his bid to oust Specter from his seat in the 2004 GOP primary by a mere 17,000 votes (out of more than a million cast).

Pennsylvania political experts say that Specter would likely face a more difficult challenge in 2010 because the Republican primary electorate in Pennsylvania has become more conservative.

“I think he has a lot of problems,” said Terry Madonna, a professor of political science at Franklin and Marshall College in Lancaster, Pa. “I think this is the test of lifetime.”

Madonna estimated that between 150,000 to 200,000 centrist Republicans switched registration to the Democratic Party in the 2008 election cycle, leaving the remaining GOP electorate more conservative.

Specter could run as an Independent, or he could return to the Democratic Party, which he left in 1965 when he made his first run for public office in Philadelphia.

Regardless of the choice, the consensus seems to be that Specter would have a far better chance against Toomey in a General Election than in a Republican Primary:

Specter would have a stronger chance against Toomey in the fall general election when independents and centrist Republicans-turned-Democrats could vote.

Democratic strategists acknowledge it would be difficult to defeat Specter in a general election because of his strong ties to labor and centrist voting record.

Democrats, meanwhile, are salivating over the idea that Toomey might defeat Specter:

Democratic strategists say that Toomey would be an easier candidate to defeat because of his outspoken conservatism, especially after Democratic voter registration jumped dramatically in 2008.

Given that Pennsylvania went for Obama by roughly than 600,000 votes, it seems clear that Toomey would have an uphill battle.