Republicans can call Arlen Specter an opportunist all they like and maybe they’re right. But the fact remains, the senator’s party jump is the direct result of the Republican’s increasing intolerance of moderates within their party.

I understand that Specter is not a model Republican and that a primary challenge is often the price a politician pays for refusing to toe the party line. But usually the main powerbrokers support the incumbent (as happened with Specter in 2004) and the official stays in office. Except, here in 2009, the Republican party is effectively controlled by talk show hosts and hardcore activists who seem to think the path back to power is through purification of the party.

This is not a syndrome exclusive to conservatives. We shouldn’t forget the purging of Joe Lieberman which resulted in the longtime Democrat becoming an Independent. Lucky for Dems, Lieberman chose to continue caucusing with the blue team, even though he did campaign for John McCain. Now with the Democrats on the verge of a 60 vote majority in the Senate (as soon as Al Franken gets his seat, God help us), I think Democratic purists may better understand the usefulness of a big tent. Without Lieberman and other less-than-pure Dems like Evan Bayh, Jim Webb, Ben Nelson, et. al., the Democrats wouldn’t be so close to a filibuster-proof majority.

Arlen Specter most likely defected because he would lose his primary. But that should still tell the Republicans something: if they want to return to power quickly (rather than waiting for the pendulum of history to swing back away from the left), they’d be better off building a broad-based coalition rather than trying to create a pure, but powerless party.

Politics Republicans Created Condition for Specter Defection