When President Barack Obama mentioned Donald Trump at his Democratic National Convention, the crowd responded as they have in the other days of the convention: “Boooooooooo.”

Obama responded with a quick line: “Don’t boo. Vote.”

It’s a classic line from Obama, going back at least his 2008 campaign. But it also shows a view he and Hillary Clinton have shared in their political careers: It’s not enough to just get angry at your political opponents’ ridiculous comments or other big problems. It’s also necessary to find a real, tangible way to overcome those issues — including something as simple as voting.