Thumbs down: Violence erupts around Donald Trump, but what triggered it?

Just when we thought political discourse couldn't descend any lower, it finds a way. Now, it's come to fisticuffs. But it's not just the violence to which we give this thumbs down. It's all the funny business that has come along with it.

For example, on Friday, GOP frontrunner Donald Trump postponed a rally in Chicago when protestors threatened to take over the event. Fights eventually broke out on the floor of the University of Illinois at Chicago arena. Then on Saturday, another rally was canceled in Kansas City after police broke out pepper spray twice in confronting protesters. Both times Trump said he had to cancel the events after consulting with local police. But in both cities, law enforcement deny having a role in encouraging him to cancel. Trump also pinned blame on organized liberal groups, particularly supporters of Democratic candidate Bernie Sanders. But there's no evidence to support that contention.

Meanwhile, Trump claims no responsibility for helping to create a political environment that seems to encourage physical confrontation, this despite his repeated stereotyping and his in-public comments encouraging supporters to punch and eject critics. Last month, he pledged to pay the legal fees of any supporters willing to “knock the crap out of” protesters in Iowa. How about just knocking out all this bombast and combative talk. Politics should not be a knock-down, drag out sport.