Giuiliani can easily afford to lose a couple hundred fanatics off of Free Republic, just as the Democratic nominee can afford to lose the couple hundred most fanatical people off of Democratic Underground.
You will see every social conservative church pastor in America speak out against abortion and partial birth abortion, pointing out that candidates who don't oppose them are not worthy of a Christian's vote. It will all be done legally, without naming candidates, but the effect will be that the Religious Right will turn dramatically away from Rudy Giuliani.