Through his own behavior — refusing to wear a mask, failing to stay six feet from the people around him, and promoting an indoor rally for supporters (who had to sign waivers saying they would not sue the Trump campaign if they got COVID-19) — the president is making clear he doesn’t care whether anyone follows the public health guidelines.

So it’s hard to fault anyone, young or old, who follows his cue.

“The government has been handing out a complicated message,” Keith Humphreys, a professor of psychiatry at Stanford, told me. “We’re asking people to open up as if the pandemic were over — while telling them that they still need to be careful. That doesn’t work; people want to hear one clear message. It’s natural for a lot of them to go for the simple message that it’s over and life can go back to normal.”

“If the president had consistently worn a mask, it would have made a difference,” he added. “If he had enforced social distancing at the podium, it would have made a difference. That was a big missed opportunity.”