Dan Larison of the American Conservative magazine:

Specter’s switch pretty well clears the way for Toomey to win the GOP nomination without much difficulty, so Toomey will have the chance to test his proposition that Pennsylvanians don’t want Arlen Specter’s brand of politics on a grand scale in the general election. The result of that contest will confirm what some of us have been saying for a while: of all the places to try to vindicate support for Club for Growth economic policy and the Iraq war, Pennsylvania is one of the worst places imaginable. If one had wanted to hasten the day when Club for Growth-style economic conservatism appeared to be nothing but a liability for the GOP, one could not have put together a better scenario than this one.