Jim DeMint’s recent encounter with Pennsylvania Senator Arlen Specter may have been the straw that broke the camel’s back and pushed Specter to abandon the GOP.

Last Thursday night on the Senate floor, Sen. Jim DeMint, R-S.C., told Pennsylvania Sen. Arlen Specter, then still a Republican, that DeMint would be supporting Specter’s rival, former Rep. Pat Toomey, R-Pa., in next year’s Senate Republican primary. DeMint says Specter “pretty much cut me off and said, ‘I’ve heard enough.’”

DeMint wouldn’t speculate whether this conversation spurred Specter to switch parties, but the conversation came within hours of the release of a poll showing Toomey leading Specter among primary voters 51 percent to 30 percent. “We knew Pat was going to win the primary,” DeMint said in a Capitol Hill interview Tuesday, minutes after Specter announced his move. “This [party switch] shouldn’t surprise anyone. It was a clever political move.”

As TNL’s esteemed Ben Domenech points out in his piece today, Defector Specter has always had one driving passion, “the right path for Arlen Specter.” This has superseded any party principles or personal convictions, and today’s move makes much more sense when viewed from that perspective. One who knew this was Pat Toomey.

Toomey had speculated in an interview with National Review’s David Freddoso that Specter might leave the party before the primary, because Pennsylvania has a “sore loser law” that prevents primary losers from running for the same office on a different party line.

If anything can describe Defector Specter it’s “sore loser”.