Look it up, kids. Fine. Here's a link.
So, the big story right now is the fact that a Donald Trump rally had to be cancelled out of concern about the violent incidents that keep happening at his rallies. Two observations.
1) Trump rallies are going to step up the security. Big time. And he probably won't hire the Hell's Angels. Security will be under strict orders to remove anyone who looks like they might protest, and protect the protester from the crowd. This is going to involve a big increase in security costs. But, hey, it isn't like Trump needs to spend money on advertising. He just needs to put an end to these incidents.
2) The media will be in a real bind. There is a general norm among journalists to cover politics as a symmetric conflict between two parties that are mirror images of each other. I have been writing recently about the problems journalists face when this isn't true. The basic problem is as follows: you can't call out one party without looking like a shill for the other, and voters are rational to discount one-sided criticism because there are so many shills out there among the media.
When Trump is the Republican nominee, journalists will face exactly this kind of dilemma. There is a reason this happens at Trump rallies, but not at Clinton rallies. If Trump's rallies keep being plagued by violent incidents, journalists will have a hard time pretending that it is a problem for both candidates. Hillary will play up the contrast, too. For a model, watch this clip of how Obama handles a protester. Then, compare that to Trump. Listen for references to coats.
Hillary will follow the Obama model of unfailing politeness. What will Trump do in the general election? If one nominee is polite and shows consideration to protesters, and the other calls for his followers to violently assault protesters, offers to pay their subsequent legal bills, and demands that protesters be thrown out into the winter weather to freeze to death without their coats, it will be impossible for journalists to pretend that the candidates are mirror images of each other.
Trump can go pretty far because any journalist who calls him out will look like a Democratic shill. But there is such a thing as too far. Trump knows this. That is why he will crack down on security at his rallies. Otherwise, journalists will be unable to pretend that the Democratic and Republican nominees are mirror images of each other.
Very soon, Trump's rallies will stop looking like Altamont. Journalists will stop talking about it, both because they have the attention spans of a puppy with ADHD, and because they would rather avoid discussing asymmetry.