The Hill indulges in some speculation regarding Arlen Specter’s political future.  With Pat Toomey suddenly looking for a rematch in a Republican primary and the RNC threatening to insert itself into the race, Specter may find the pastures greener on the other side of the partisan fence:

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.

Specter can blame Operation Chaos for that development.  In 2008, over 150,000 Pennsylvania Republicans switched to the Democratic primary to vote for Hillary Clinton over Barack Obama.  Most of those were centrists and moderates, and most of them haven’t switched back.  If they stay out, they won’t be able to participate in the closed Pennsylvania primaries in 2010.  Specter’s close shave in 2004 would almost certainly transform into a lopsided defeat under those circumstances, especially with his vote on Porkulus.

Would switching parties help him?  Specter barely beat Toomey in 2004 with Bush’s backing, when times were still good, in a Republican primary with the moderates.  As a Democrat, he might command those centrists to his banner, but only if Porkulus shows miraculous signs of working by the spring of 2010.  If not, Toomey and his fiscal conservatism will look much better to working-class Pennsylvanians, who will be in the mood to clean house (and House and Senate).

Switching parties now will almost certainly eliminate any chance of holding a filibuster for Mitch McConnell, but it may be difficult to tell the difference at this point.  Specter’s failure on Porkulus kept the GOP from demanding meaningful input into the stimulus package, a rather significant betrayal.  He’s more than likely to vote for Card Check with his ties to big labor, or at least vote for cloture on the measure to allow it to come to a vote.  He might stand firm against FOCA, but that’s a long shot.  I’m not aware of a single significant part of the Obama agenda on which the Republicans can rely on him to help with a filibuster.

Most Republicans won’t mourn his departure at this point.  Normally I’d argue for the big tent, but Specter doesn’t appear ready to rebut Obama at all on any policy.