He is freepers/tea-partier’s affirmative action candidate. When a candidate has a ‘true conservative’ label, these voters will just ignore all other qualifications. This is crazy, no different than liberals!
Santorum used to be so liberal, and of course pro-abortion, that might be seeping out to some voters.
A past where he is anti-Reagan and supports pro-abortion fanatic, Arlen Specter for President, can turn off some primary voters when they learn about it.