“Why does anyone care?” That’s one of the emerging lines being offered in defense of people who, despite having been fully vaccinated, have chosen to keep wearing masks. Generally, I agree with this. I don’t particularly care what anyone else does. Line yourself in lead if you wish to. It’s not my business.

But I can’t help but notice that those who are now touting this approach have been at least a little selective with it. When Joe Biden was wearing a mask long, long after he needed to, we were told that he was justified in doing so in order to “send a signal” that Americans should be wearing masks. That signal, we were informed, was one that President Trump had singularly failed to convey.

Okay. Fine. But, if signaling matters, surely it matters in all directions? Unlike a year ago, the primary aim of America’s public-health officials now is to encourage as many Americans as possible to get vaccinated. And a key way of doing that is to confirm that the vaccine works by showing that, once a person has been inoculated, he no longer needs to wear a mask. Yes, it is not the end of the world if people in influential positions decide that they will ignore the science and embark on a five-year-long snorkel-wearing kick. But it does send a message. As ever, “Who cares?” can cut both ways.