The rise of the new Know-Nothings
Don't kid yourself.
It's a movement of populists- and to a great extent, as the Trump phenomenon shows, of Know Nothings. Granted, there are security concerns involved in the general revulsion against undocumented immigration from Mexico and refugees from Syria and other countries with large Muslim populations. But it would be absurd not to recognize that there is also the same kind of nativism and prejudice that once led to signs reading "NO IRISH NEED APPLY" and general antipathy against the immigrant ancestors of many of the very people who are backing Donald Trump now.
To a not inconsiderable extent, it's a revolt against conservative and libertarian orthodoxy alike. If anything, it's anti-ideological- which explains how somebody with the checkered past and current ideology of Donald Trump can benefit from it.
This is going to be a rough election for the Right. It's an election that should be the Republican party's to lose. Hillary shouldn't have a chance. But at this point, I have a strong hunch that the Great Republican Revolt of 2015 will ultimately benefit Hillary Clinton and nobody else.
It's effectively removed policy from the campaign. Which is how somebody like Trump- who literally changes the subject every time anybody asks for policy specifics and admits to getting his foreign policy and defense policy advice from TV programs- can be dominating the race for an office for which he has not the slightest qualifications and about whose concerns he has not the vaguest clue.