Today's withdrawal by Dede Scozzafava in the NY23 special election to Congress is an important milestone. In her statement, she says "It is increasingly clear that pressure is mounting on many of my supporters to shift their support." It's a polite way of noting that the far-right conservatives -- mostly outside the district -- have successfully purged her for perceived disloyalty to conservatism.
This must be a very unwelcome development for Frank LoBiondo. To be sure, he's "pro-life" and part of the Gingrich's Revolutionary Class of 1994, so he has right-wing credentials she doesn't. But his occasional moderate votes are increasingly unwelcome to conservatives both inside and outside of Congress. His vote in favor of the energy bill earned him attacks nationwide by outraged conservatives. There's many who would love to get rid of him.
Now, LoBiondo, unlike Scozzafava, has lots of money and the advantage of incumbency. It's now possible to imagine a successful challenge to him, but it's extremely unlikely. But today we see one more step down a road along which moderate Republicanism is extinguished.