Conservatives will never "unite" around a Leftist like Giuliani or Romney. We oppose liberals and the destruction they are bringing on our country. Is that too complicated for you?
Then we'll lose. That is what you want.
So when the general election comes around and you go into the booth and possibly see one of the 3 more moderate candidates there with an "R" and Hillary or Edwards or Obama with their "D"...what do you do? If you choose some 3rd party candidate, history shows you what happens with enough of that response. Last time some of us foolishly chose the 3rd party option in great numbers we ended up with 8 years of deterioration of ALL we believe in with the Clintons. Is that what you want, just so you don't support truly "the lesser of 2 evils" (from your perspective)?