A very long read but also a well worth your time account of how Republicans reached their current predicament and what are their choices from now on.
http://www.theatlantic.com/magazine/archive/2016/01/the-great-republican-revolt/419118/White Middle Americans express heavy mistrust of every institution in American society: not only government, but corporations, unions, even the political party they typically vote for—the Republican Party of Romney, Ryan, and McConnell, which they despise as a sad crew of weaklings and sellouts. They are pissed off. And when Donald Trump came along, they were the people who told the pollsters, “That’s my guy.”
They aren’t necessarily superconservative. They often don’t think in ideological terms at all. But they do strongly feel that life in this country used to be better for people like them—and they want that older country back.