Demonstrators wearing face masks kneel in front of the Trump Towers in Istanbul, Turkey, during a protest on Friday. (Murad Sezer/Reuters)

In a few weeks, one of two things will have happened. Either covid-19 cases will abruptly reverse their decline in some of America’s largest cities, and we will know that they were seeded by the days of rage we are living through . . . or they won’t. Either way, social distancing is over.

In the happy scenario, the protests will have performed an enormous public service, even beyond agitating for justice. They are basically running a natural experiment that scientists could never have ethically undertaken: Do massive outside gatherings — including singing, chanting, screaming and coughing — spread covid-19, or not? Along with evidence from the Memorial Day weekend parties at Missouri’s Lake of the Ozarks, they may well demonstrate, once and for all, that the risk of spreading covid-19 outdoors is negligible. At which point, throw open the bar patios and backyard barbecues! Bring on the beach-blanket bingo! Move church pews into the parking lot and sing away!

Unfortunately, it’s also grimly plausible that in a few weeks we’ll see new outbreaks that will soon surge out of control, taking many American lives. Because we’ll never be able to lock down our cities again; once you’ve let the cat out of the bag, kitty won’t allow himself to be stuffed back in.

Nearly 6 in 10 Americans who are working outside their homes are concerned that they could be exposed to the virus at work and infect their families. (Video: The Washington Post)

One hears a great deal of magical thinking on this point: Public health experts who believe covid-19 will spread among protesters but assert that, on net, they’ll save lives, because systemic racism already cuts short so many black lives. This is wishful woo on the order of “tax cuts raise revenue.” Improving life expectancy is the work of a generation, not a week; at best, the protests might very slightly narrow those appalling gaps between white and black life expectancy. At worst, the virus will attack the people protesting and actually widen them.

The less fanciful experts acknowledge this, then add that the cause is worth it, unlike the earlier activities public health officials shut down. This, now, is a real argument: Some things are worth dying for. The equality of every American before the law certainly sounds like one of them to me.

Full coverage of the George Floyd protests

But there are reasonable counterarguments: First, as was pointed out when red states were protesting, you may have every right to risk your own death, but with infectious disease, protesters also risk killing other people, who might not have volunteered to die for your cause. Which brings us to the second caveat: In a diverse and highly pluralistic society, authorities don’t get to declare some causes worthy and others worthless.

It may seem obvious to you that ending police brutality rises to a level of importance that, say, church services don’t. But the impossibility of rank-ordering competing ideas about what is “most important” is the reason liberal democracy had to be invented. If you were a religious believer, you might rank church higher; if you were about to lose your house unless your business reopened, you might put nail salons high up on the list.

As individuals, we can make those distinctions. But our authorities may not except on broadly neutral terms. Some public officials seem to imagine that if they can distinguish between selling food and offering Communion, they must also have the authority to make even finer distinctions: allowing people to exercise their First Amendment right to protest police brutality, while circumscribing their First Amendment right to worship in public. Legally, I doubt it, but I’m quite positive that courts won’t let governments distinguish between assembling to protest police brutality and assembling to protest public health policy.

One can, of course, argue that there’s a moral difference. But moral distinctions have no force outside the community that makes them. However satisfying it feels to call one sort of protest “suicidal,” “reckless” and “mind-bogglingly selfish,” while describing the other as a noble and necessary fight against injustice, this will not restrain the disdained. Indeed, the perceived hypocrisy will deafen them to anything said after that.

So if it turns out that covid-19 can spread outside, if enough people gather close together, it will be too late to do anything about it. Public health officials will have forfeited their legal authority; media outlets and cultural leaders who have been much more sympathetic to protests than other sorts of gatherings will never persuade anyone who differs to go back inside. The disease will spread unhindered by anything except private, prudential decisions to avoid other people.

Full coverage of the coronavirus pandemic

I have every hope that this won’t matter, and that in a few weeks we’ll find out that covid-19 simply doesn’t spread much outdoors. But I also have lots of fear that we won’t, and that private, prudential decisions won’t be enough to stop the resultant outbreak. Because, as a society, we’ve now got nothing else left.

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Read more:

Read a letter in response to this column: Protests could have an unexpected social benefit

Michelle A. Williams and Jeffrey Sánchez: Racism is killing black people. It’s sickening them, too.

Jennifer Rubin: Maybe there is no floor for Trump’s support

Megan McArdle: Cities will make a comeback after the coronavirus. They almost always do.

Joe Biden: How the White House coronavirus response presents us with a false choice

Ishaan Tharoor: A wave of protests puts a spotlight on U.S. hypocrisy

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