Newt is fading and Rick Santorum is rising as the final "anyone but Mitt" candidate. The fact that he is the last person in the race who has not achieved this distinction says a lot about his qualifications. He is a former senator with no executive experience. He is also a fierce social conservative.
Personally, I think that Santorum would be a disaster for the Republican party. His views on sex and marriage mirror those from the first half of the 20th century. In his book, It Takes a Family, he makes his positions clear. He is against premarital sex, contraceptives for married couples, divorce and women working outside of the home. His position on gay marriage earned him a Google-bombing. While it is perfectly acceptable for someone to hold these opinions, he has implied that the government should enforce them. That puts him at odds with most of the country. He is just plain unelectable.
He has also hurt the Republican Party. They scored some points against Obamacare forcing religious institutions to pay for services that they do not agree with but now Santorum has changed the conversation away from religion to birth control with his opinion that birth control is harmful to women.
Between them, my wife and daughter have violated about everything that Santorum believes about women should behave. I can't support a candidate who would disapprove of my family and I expect that most of the country agrees with me on this.