Presidential candidates – and presidents, once they take office – get hecklers all the time. Some aren't audible at large events, and the speaker just keeps talking. Others are quickly ushered away by security guards or Secret Service agents. And most of the time, it's a simple process: Wait for the heckler to be taken away, and resume speaking.
But from time to time, a persistent heckler can really annoy a candidate, or even a president. Trump's threats of violence betray an increasing frustration with interruptions. Even so, most of those hecklers don't earn threats of violence.
Chris Christie told a heckler to "sit down and shut up" during a speech last October. Hillary Clinton called a heckler "very rude" in January, saying, "I am never going to call on you." President Obama famously quieted a heckler at an LGBT Pride Month event at the White House last year, saying, "You're in my house! It's not respectful." And in perhaps the crankiest response to a heckler in the past few decades, Ronald Reagan once told a heckler, "Aw, shut up!" at a rally in Michigan in 1982.
A history of presidential hecklers makes Trump's frustration somewhat unsurprising – although his overt threats of violence are something new (and "something new" is apparently what his supporters are looking for). And in Trump's case, dealing with protesters forcefully just helps boost the Trump brand even more.