Andrew Sullivan said it

But the GOP is now the Big Government party. And its deficit-mongering will mean higher taxes in the not-so-distant future. You have to believe that the terror gap between Kerry and Bush is simply massive to acquiesce in Bush's domestic policies: fiscal insanity, social intolerance, and creeping theocracy. Bush has moved the GOP toward being the political wing of fundamentalist evangelicalism. If you're not born-again, you increasingly do not belong there. In four more years, heaven knows what he will have accomplished. But, then, many of you think the difference in foreign policy is so great nothing else matters. That's the calculation. You have to weigh the damage Bush is doing domestically with the damage Kerry might do internationaly."

I have to say I'm harder on Bush and not as hard on Kerry, but Sullivan has really identified the basic choice to be made. Not to mention if Shrub were to nominate a few Supremes during a second term....