So far, this is what I see:
My man Ron Paul - ENTP, very professorial in many of his answers, extremely P (uses phrases like “may not be” and “possibly”, always exploring possibilities). Far too extroverted to be an INTP. Definitely fits ENTP crazy genius stereotype. Haven’t come across an INTP politician ever, for that matter.
Mitt Romney - ESTJ, the ‘good student’, responsible family man, gracious competitor, pillar of the community who values cooperation far above any kind of intellectual consistency. Thinks of becoming President as a ‘promotion’, has no fixed ideology, believer in ‘best practices’ and ‘common sense’, whether or not they apply to a situation.
Newt Gingrich - ENTJ, by instinct, the best debator of the bunch, always on the attack, policy wonk, grand ideas, extroverted utilitarian J, sadly opportunistic and values winning over scruples
Rick Perry - ESFJ? too out-of-step to be an artisan, too S to be an N. Does not seem to be able to respond in debates fast enough to be Te, but still definitely extroverted. Seems to have Fe responses during debates.
Can’t take Jon Huntsman and Rick Santorum seriously enough to analyze.