The Atlantic article up there somewhere traces the split back to when ACA was first introduced. This is an excerpt:
"We followed the most radical voices in the party and the movement, and they led us to abject and irreversible defeat.
There were leaders who knew better, who would have liked to deal. But they were trapped. Conservative talkers on Fox and talk radio had whipped the Republican voting base into such a frenzy that deal-making was rendered impossible. How do you negotiate with somebody who wants to murder your grandmother? Or—more exactly—with somebody whom your voters have been persuaded to believe wants to murder their grandmother?
I’ve been on a soapbox for months now about the harm that our overheated talk is doing to us. Yes it mobilizes supporters—but by mobilizing them with hysterical accusations and pseudo-information, overheated talk has made it impossible for representatives to represent and elected leaders to lead. The real leaders are on TV and radio, and they have very different imperatives from people in government. Talk radio thrives on confrontation and recrimination. When Rush Limbaugh said that he wanted President Obama to fail, he was intelligently explaining his own interests. What he omitted to say—but what is equally true—is that he also wants Republicans to fail. If Republicans succeed—if they govern successfully in office and negotiate attractive compromises out of office—Rush’s listeners get less angry. And if they are less angry, they listen to the radio less, and hear fewer ads for Sleepnumber beds."