I step away from the blogotubes for a couple of hours and my senator goes and switches parties.
My instinct is that he'll go along with the Democratic caucus on cloture (which is outstanding news), but he'll be mavericky on other votes. In other words, we'll hopefully have him where it counts, and he'll be with the Bayh Dogs on everything else.
But the broader thought here is that this is a huge warning sign for the Republicans. Yes, Specter was going to lose to Toomey in the primary. But the very fact that he was challenged by a wingnut and then had to entirely flee -- not to become an independent, but to entirely flee to the Democrats -- is a clear sign that the Republicans are further marginalizing themselves by throwing in with the Limbaugh/Beck wing of the party and leaving Republican moderates to die on the vine. Not a good prospect with an Obama-friendly independent electorate exceeding GOP identification by 17 points.
Adding... I wonder if Norm Coleman donations spiked today.