From Philip Klein at National Review (emphasis is mine):
[A]t a pivotal juncture in American history, the best hope for replacing President Obama now rests with a man who claims to be “severely conservative” with the same degree of conviction he once conveyed when claiming to be “progressive.”
In a new e-book, Conservative Survival in the Romney Era, I try to reconcile two competing responses on the right — disillusionment on the one end and a desire to reflexively fall in line behind Romney on the other.
Clearly, sitting out the election isn’t an option for conservatives, given the need to defeat Obama. On the other hand, refraining from criticizing Romney now that he’s the presumptive nominee would lead us down a treacherous path.