Perry and Gingrich both blew their chances already. Santorum is both more conservative than and a better potential general election candidate than both of them.
Santorum is a solid conservative, but he also lost his home state of PA by 18 points in the 2006 Senate race. Sorry, but nationally he is dead in the water. He has no organization and the stink of that crushing Senate defeat leaves too many electability issues for Rick to have any chance to win the nomination. The big money will never go to his campaign and it will be easy for any candidate with money and organization to tear him to shreds. Santorum won't be the nominee. Santorum needs to go back to PA and win something to erase the stench of losing his last race by 18 points and regenerate confidence in potential supporters that it is worth risking money and time to back him.