He makes the argument here, here, here, here and here. (do a search for "evangelical" since many of those posts contain lengthy discussions of other topics)
His argument is weak and in effect he ends up proving that Bush's nomination will imperil the Republicans in the next election. Sure, MAYBE Evangelicals will stay home on election day. But it's much more likely that the base, mad over the broken promise to appoint Justices like Scalia and Thomas, will sit out the election. There seems to be no hope that the Court will ever be fixed, and thus no reason to vote Republican (the Court rules over so much of our lives that having the Democrats in charge means little difference, especially since the Republicans aren't conservative these days to begin with). Hewitt actually seems to be playing up the identity-politics of evangelicals, courting their influence in pressing for Miers' nomination merely BECAUSE she's an evangelical (as opposed to being a good lawyer, like John Roberts).
Look. Some elections are very close. Some, like the 2000 Senate contests in Washington State and Missouri, or the 2002 contest in South Dakota are decided by handfuls of votes. It doesn't have to be an epic departure of an entire cosntituency to cripple crucial races. Playing with fire over nominees --and especially attacking those who at least deserve the benefit of the doubt and at best deserve a strong and determined defense-- is terrible politics.
The response will be that "the base" cares about judges --of course they do. They cared enough about Bush's nominees to get very active in 2002 and 2004 on that issue. Now the critics are saying Bush has lost his way and is losing the issue. These critics aren't just refusing to dance with the one that brought them, they are denouncing the idea of even having traveled to the ball in his car.
Exactly, Hugh. Elections are close. Playing fire over nominees IS terrible politics. Which kinda makes you think - what the HELL was Bush thinking playing fire over this nominee? Moreover, his response has backwards logic. It's not that the Critics are refusing to dance with Bush, who supposedly brought THEM to a ballroom dance. No, Hugh. WE elected Bush. We brought him to the dance. We're the ones driving the car. Bush is along for OUR ride. He's OUR person we hired to to the job WE saw fit. If WE don't like it, HE and his Republicans can take a walk home from the ball.
Hugh therefore sees that the argument cuts against him, but he fails to properly respond to the charge that "the base" that cares about judges will be the tipping point in the elections, and not that evangelicals will. I should also note that it's likely that evangelicals probably overlap to a large degree with "the base" that cares about judges and that they, again, probably don't give a fig about identity-politics.
Moreover, it seems unlikely that Republicans, supposedly against affirmative action and identity politics, would suddenly vote in droves for the Democrats or stay home merely because an unqualified evangelical cipher was defeated for the Court. There are plenty of other evangelicals that Bush could've nominated that are conservative and publicly committed originalists.
Frankly, all the discussion I've seen about people sitting out the next election are Catholics mad that Bush missed an opportunity to regin in the runaway Court. And now we must apparently wait another 20 years or so before a swing-vote opportunity opens up to shift the Court to the right. With Harriet Miers an unrepentant believer in diversity, she moves the Court to the left, away from the people and away from the Constitution.