The Omicron variant of COVID-19 has case rates spiking exponentially across the United States, and though hospitalizations and deaths haven’t followed anything like the same pattern, the sheer size of the caseload means those numbers are ticking upward, too. The difference between the two paces is partly due to Omicron’s comparatively mild effects, but widespread immunity from a combination of initial vaccination, boosters, and recovery from previous COVID cases is an obvious factor, too.

That latter point has many escalating calls for broad vaccine mandates, perhaps as a condition of commercial air travel (as my colleague Ryan Cooper has argued) or perhaps copied from somewhere like France, where a law passed Sunday will ban unvaccinated people — including those who have tested negative or have proof of recent recovery — from restaurants, sports venues, theaters, all domestic flights, and some trains.

I’m skeptical such a mandate would be effective here in the States. I anticipate, as Freddie deBoer has put it, that “there would be an absolute deluge of lawsuits the minute any universal mandate was formalized as policy, and it would be years before anybody would be forcibly inoculated.” Moreover, as enthusiastic as I am about vaccines, I can’t get behind injecting things into other people’s bodies at the tip of the sword.

But the pro-mandate crowd is evidently untroubled by that prospect — or, more charitably, believes that the government’s interest in public health here outweighs the individual’s interest in liberty and that even a slow, lawsuit-ridden mandate is better than no mandate at all. But if neither pragmatics nor principle are enough to nix the mandate urge, let me raise one more reason: blowback.

Perhaps the first contemporary political book I read was Chalmers Johnson’s Blowback: The Costs and Consequences of American Empire. Published in early 2000, Blowback predated by 18 months the 9/11 attacks and subsequent foreign policy disasters that would make its titular term mainstream. I came to the work as a political science major in 2007 or 2008, spurred by a growing interest in foreign policy (and that my then-not-boyfriend, now-husband could be seen holding it in a photo on Facebook).

Blowback felt a little scandalous on that initial read because my upbringing was conservative. Anything which might be construed as “blaming America first” at that time remained vehemently verboten on the right, a glaring violation of what I’d now call “patriotic correctness.” There was nothing among mainstream Republicans in 2007 like former President Donald Trump’s observation a decade later that the U.S. government, just like its Russian counterpart, kills people. We were the good guys, full stop, and as for the motives of those who attacked us — well, “they hate our freedoms.”

Johnson’s thesis, as he writes in his first chapter, is that there’s a bit more to it, actually: that Americans “have created an empire;” that there are “consequences of our imperial stance for the rest of the world and for ourselves;” that “there is a kind of balance sheet” of U.S. actions abroad “that builds up over time;” and that — because not all those actions are positive for the people who experience them — they’re “likely to build up reservoirs of resentment against all Americans … that can have lethal results.”

“Blowback” is the CIA term for those results, for unintended, negative consequences of U.S. foreign policies, especially those kept hidden from the American people (like U.S.-orchestrated coups) or which we haven’t seriously considered as a plausible prompt of foreign anger (like the existence of roughly 800 U.S. military bases in dozens of nations worldwide). The word is not a term of moral judgment but an observation of the world — and human nature — as it is, a recognition that people in other nations love their families, friends, homes, cities, and holy places, just as we do, and will tend to react with anger at their violation, just as we would.

To acknowledge the reality of blowback is not to say the specific retaliations those people choose are just or legitimate. Often, they are not. But they are intelligible and, to a degree, predictable. If U.S. drones aimed at a terrorist instead kill an innocent farmer’s wife and maim his children, we should hardly be surprised if he becomes hostile toward America, maybe even becoming a terrorist himself.

Libertarians and the left understood this before most conservatives did. When blowback was controversial in the aughts, when I first encountered the idea, that was the line of division. Now, as sweeping COVID vaccine mandates are under debate and mostly favored on the left, blowback seems to be a timely concept once again.

If our government were to implement vaccine mandates for so much of ordinary life — to ban unvaccinated adults from restaurants, planes, and so on — do we imagine there wouldn’t be blowback? Do we imagine there would be no unintended consequences of barring a large portion of the country from public recreation and transit? Some small businesses, of course, would quietly decline to comply, continuing to deal with unvaccinated patrons. But with major companies, and especially highly regulated ones like airlines, enforcement could be consistent, and higher vaccination rates would not be the only effect.

Parts of Western Europe offer a partial preview of the enormous resentment and alienation this would produce among those determined not to be vaccinated. “People without a [vaccination] certificate like me, we’re not a part of society anymore,” a Swiss vaccine mandate critic named Nicolas Rimoldi told CNN for a report published Sunday. “We’re excluded. We’re like less valuable humans.”

Rimoldi and those like him are “falling out of society,” CNN’s headline summarized, and insofar as the effects of a mandate would be different here than in Europe, I only see them differing for the worse: We have a stronger culture of individualism and defiance of centralized power. Ours is a larger country where domestic air travel is more needful. As progressives themselves often note, we have many more guns. And even if, say, only 10 percent of U.S. adults persistently defied the mandate, that’s still about 26 million people, three times Switzerland’s entire population.

Do we want to tell 26 million people they’re not part of our society anymore? Isn’t the risk of that route self-evident?

Sure, we might only get blowback from a small fraction of that small fraction, and I’ve been fairly skeptical of claims that we’re on the verge of a new civil war. But if the federal government pushed millions of people out of normal life? If it sent all those people “falling out of society”? Gave them reason to believe they could never again live like they did c. 2019 under our current system of governance? Never again fly to visit their parents or grandchildren, never eat at a chain restaurant, never watch a ball game in person, never see a movie in theaters?

Well, then my expectations around civil strife might begin to change. This is just the sort of thing that could push a significant number from “playact[ing] extremism” online to becoming real-life extremists.

Mandate advocates, understandably, couch their arguments in terms of safety — but then, so do many advocates of American empire. Good intentions don’t change the realities of blowback in foreign policy, and I don’t think they’d change the reality of blowback from a domestic vaccine mandate, either. In both cases we must consider whether a naive plan meant to save lives could lead to more tragedy instead.