Do presidents’ popularity increase after assassination attempts? History has an answer.

In the 2010 movie “Machete,” Sen. John McLaughlin of Texas (played by Robert De Niro) stages an assassination attempt to frame the title character. A newscaster in the film reports that a poll, taken within minutes of the fake shooting, shows McLaughlin at record-high approval ratings.

It’s part of a popular belief that when high-profile political figures survive assassination attempts, their approval ratings skyrocket.

So will Donald Trump — having survived an assassination attempt Saturday when a gunman wounded his ear ...