Perhaps...but if you hold you vote and allow a socialist like Clinton...or a whackjob like Gore...or a whatever the hell Kerry is... to win, then are you any less 'guilty'?
I'm a conservative. As such, 99% of the time I find myself voting Republican with a few exceptions, like Arlen Specter whom I refuse to support in any way.
I believe that nominating Giuliani as the Republican standard bearer will set the conservative movement back immeasurably and lead to the demise of the GOP. An endorsement of Giuliani's ideology will strip the Republican party of any claim to being the party of pro-lifers, second amendment supporters, constitutionalists, small government, fiscal restraint or traditional values.
Giuliani is the antithesis of everything I believe in. He is a big government, pro-abortion, pro-special rights for gays, anti-gun, country-club Republican with a disturbing authoritarian streak and a nonexistent personal morality.
While I believe a Giuliani nomination guarantees a GOP loss, if others who don't want to say I'm "guilty" by not supporting him so be it. I will not actively support the destruction of my own beliefs.