It's weird to be saying this for (I think) the second time--but here is a good article by David Frum, regarding the dilemma that Republican conservative voters face in the US right now:
http://www.theatlantic.com/politics/...o-vote/504977/
Although I am not of that stripe I can sympathize with the issues set out here, and while we are all mocking the GOP for nominating such an obviously unqualified boor, it is worth asking: what if Democrats had done the same? What if Trump were running as a Democrat against a tarnished and unpopular but still-competent GOP candidate? (Romney 2.0, let's say).
I suspect the shoe would be on the other foot in every sense, and though Romney would likely win (for the same reasons that Clinton will likely win) there would be a lot of "deplorable" democrats holding their noses and casting ballots for Trump. It is an unhealthy side effect of the polarized two-party system.