“Ninety percent of a director’s job is casting,” about a thousand movie directors have said over the years, from William Wyler to Robert Altman. It means: get the right people in the right parts so they can play to their strengths. As a filmmaker, I can vouch for the wisdom of this. Otherwise, you spend all your time pulling something out of someone that may not be natural for that actor, and of course the thing we love most about acting is when it seems the least like acting.

The Biden campaign would do well to remember this as it contemplates how to best use their candidate. He has a set of strengths that used to be not worth mentioning, because any decent person had them, but now they shimmer like diamonds against the rancid tar pit of his competition: his down-to-earth-good-guy quality. His sense of empathy, even sweetness. His readiness to laugh. He has a great smile—not calculated like Bill Clinton’s or Ronald Reagan’s, not creepy like Jimmy Carter’s, or joyless and strained like Nixon’s, but a genuine flash of fun that says, “Listen, folks, it’s a nuthouse out here, and we gotta laugh to keep going.” He’s no visionary, but he believes in the Constitution and international alliances and science. And he knows how to hold a Bible.