James Robbins writes at USA Today that the rioters protesting Donald Trump's appearances and rallies might well swing public opinion in Trump's favor. Most voters don't hold with rioting and those doing it.
Robbins reminds us Nixon used the rioting at the Democratic convention in 1968 to cast himself as the law and order candidate. He made opponent Hubert Humphrey look like a riot sympathizer. Trump has already made the same claim with regard to Sanders.