There are key points of conservatism, too, though I am actually somewhat libertarian by nature. If a candidate's record violates one or two-- well ok. But on several points illegal immigration, foreign policy expertise, anti-tax or fee raising, pro-life, and pro-2nd amendment: Romney is deficient or fails. Guiliani fails. Paul fails. McCain fails big time. That leaves Fred Thompson.
Fred believed in pro choice and amnesty for illegals at one time. He is a more recent convert to strong stances to both, but somehow you rail on Romney. Romney has been a conservative all his life and attested to by many.