Barry Goldwater lamented that the GOP was being taken over by the religious right, and he was completely correct. It helped win elections a few decades ago but in this era of shifting demographics it has locked the party into a no-win situation as conservatism has become synonymous with moral superiority in the name of religion. They either lose at least some of the reliable voting bloc of evangelicals or keep them at the expense of attracting new voters.
Trump is the first time in a while we've seen a populist movement gain so much steam in the GOP. He has no political principles whatsoever, and is probably the most liberal candidate on the GOP side on most issues, but he has found popularity because people are sick of the status quo and really don't like how traditional America has come under fire. It's kind of a watershed moment, but I think things may get worse before they get better. The party just has no unifying vision and anyone who deviates from the alpha "true conservative" prototype even by a little is mocked and derided. Imagine if Reagan ran today - Trump supporters would be calling him an establishment stooge.
