Specter does a good job for Pennsylvania.
He's also our senior Senator.
He wants to keep his job. Don't we all.
He could retire tomorrow, with a sizable pension. He's been fighting cancer for years. It wouldn't hurt him to take retirement. But he likes his work.
Pennsylvanians like him, too.
If Pennsylvanians don't like him anymore, now that he's running as a Democrat, the right-wing guy the Republicans will run will win.
Specter will run against the Republican Party's chosen one. He's not going to avoid that contest, but this way he will control the pool of voters. This way, Pennsylvania votes for or against him, our senior Senator. He gets a referendum on his performance. And we get to have our choice as a whole state, without having our choice pre-empted .