Interesting blog post about Arlen Specter at the Whitman-Danforth group:

Specter knows that this dance he does is an irritant to GOP leaders, and he has been careful not to poke his finger in their eyes too often. On balance, he is still more loyal than disloyal. Sometimes he strays at first, only to run back home just in time. Last month Specter surprised everyone when he dropped his support for “card check,” the controversial labor bill that would make it easier for workers to unionize. Most Republicans strongly oppose it, making Specter’s vote critical to Democrats.
“He was a goddam cosponsor!” a Democratic strategist seethed to NEWSWEEK. (He asked not to be named slamming the senator.) Specter says he felt the bill would hurt businesses already burdened by the recession. Strategists from both parties saw the flip-flop as a calculated move to shore up his standing with Republican voters—and donors—after abandoning them on the stimulus vote.
This is the trouble for Republicans and Democrats who want Specter’s blessing: there’s no telling how he will use his swing vote. The White House is trying to win him over. Specter has “the rarest of all combinations,” Joe Biden said in a recent speech in Pennsylvania. “It’s the profound intellect to comprehend what is most important for the country, and the willingness … to risk your career for it.”
Republicans can’t quite muster Bidenesque levels of obsequiousness when it comes to Specter, but they try. “I’m very happy to have Arlen Specter as a colleague,” says GOP leader Mitch McConnell. “He is almost always there when I need him.” Others are less diplomatic. “I certainly don’t have any comment about him,” John McCain said with a huff when a NEWSWEEK reporter asked for his thoughts on Specter last week.
Specter can handle the wrath of his colleagues. The greater danger is that he winds up on the wrong side of the voters. His former Republican challenger, Pat Toomey, is raising money for a rematch next year. State party officials aren’t thrilled with Specter, but worry he’s the only thing keeping the seat from going to a Democrat. Republicans are still very angry about the stimulus vote, and Toomey, a fiscal conservative, will use it against him. “If it costs me my seat, I’m prepared to eat it,” Specter says. Does that really concern him? “Of course it does,” he says, his impatience rising. “What do you think I am, a mo-ron?” Hardly. Call Arlen Specter what you will (everyone else does), but you certainly can’t call him that.

I’m not sure who wrote it, but it’s a pretty good analysis of the PA GOP senate primary race.