The supporters with the best grammar were those of Lincoln Chafee. Behind him were those of Jim Webb, Bernie Sanders, Martin O'Malley, and Hillary Clinton. Oddly enough, the two candidates with the most literate fans used to be Republicans. That's interesting and possibly a little perplexing, because all the Democratic supporters write at least as well, if not better, than even those of any Republican.
Follow over the jump for a side-by-side comparison in Grammarly's Presidential Debate Grammar Power Rankings.
Hillary's supporters may have the poorest writing mechanics of any of the five Democratic candidates, but they write just as well as those of Carly Fiorina, the best writers among all the Republican supporters measured. All the rest of the GOP partisans examined had far worse writing skills, with Trump's fans making exactly twice as many errors than Clinton's, more than thrice those of Sanders, and quadruple those of Chafee. Then again, I shouldn't be surprised. The people who like Trump are the kind who would make signs like this.
I guess Chafee and Webb may have left the Republicans in part because the party has become too stupid for them. That certainly was the case for me.