Wikipedia Table
Found it interesting in light of it being in the news. Trump got only 13%, the worst performance by a Republican since 1912, and 9% worse than Romney. Though it's been on a rapid decline - from R-leaning in the 50s and 60s, to voting in the 40%s from 1976 to 1988, 30%s from 1992 to 2000, then 20%s from 2004 to 2012.
(Not saying that this really tells us anything about the white supremacist rally).
Then why'd you post it?
Because it's interesting, and this is a forum about political data?