I have always thought that Duncan Hunter was really running for President so that he could be a realistic nominee for Vice President.
Giuliani or Romney will need a running mate that settles the social conservatives down, while still being well spoken and principled.
Hunter is not the only potential guy for this - Brownback and Huckabee and others might fill this bill also.
Brownback would cost whoever chooses him as VP. That man is an absolute snake and shouldn't be permitted anywhere near the WH.