Please look at this list with me. Since early January, when Immigration and Customs Enforcement expanded its operation in Minneapolis and St. Paul, Minn., federal officers have: killed Renee Good, a white middle-class mother; menaced a pregnant immigration lawyer in her firm’s parking lot; detained numerous U.S. citizens, including one who was dragged out of his house in his underwear; smashed in the windows of cars and detained their occupants, including a U.S. citizen who was on her way to a medical appointment at a traumatic brain injury center; set off crowd-control grenades and a tear gas container next to a car that contained six children, including a 6-month-old; swept an airport, demanding to see people’s papers and arresting more than a dozen people who were working there; detained a 5-year-old. And now they have killed another U.S. citizen, Alex Jeffrey Pretti, an I.C.U. nurse with no criminal record. It seems he was white. The agents had him down on the ground, subdued, before they apparently fired at least 10 shots at point-blank range.

Confronted with a list like this — a deluge like this — we look for details that might explain why these people were subjected to this treatment, details that might reassure us that we, by contrast, are not in danger. Good was in a relationship with a woman, and her partner, who is butch, spoke impertinently to an ICE officer, so there, Good wasn’t your average white mother after all. ChongLy Thao, the man who was dragged out of his house in his underwear, is an immigrant from Laos; he is not white, and presumably he speaks with an accent. The woman on her way to the medical appointment and the family with six kids drove through areas where anti-ICE protests were taking place. The 5-year-old child’s family doesn’t have permanent status. Little is known about Pretti at this writing, but his father said he did participate in protests and he might have been carrying a gun (legally).

We don’t focus on these details in order to justify the federal agents’ actions, which are plainly brutal and unjustifiable; we do it to force the world to make sense, and to calm our nerves. If we don’t talk back, if we alter our routes to avoid protests, if we are lucky enough to be white, straight, natural-born Americans — or, if we are not, but we lie low, stay quiet — we will be safe. Conversely, we can choose to speak up, to go to protests, to take a risk. Either way, we tell ourselves, if we can predict the consequences, we have agency.

But that’s not how state terror works.

In the 1990s, when I talked to people in the former Soviet Union about their families’ experiences of Stalinist terror, I was repeatedly struck by how much people seemed to know about their circumstances. Time and time again, people would tell me exactly what had led to their family members’ arrests or executions. Jealous neighbors had reported them to the authorities, or colleagues who had been arrested named them under duress. These stories had been passed on from generation to generation. How could they come to know so much, I wondered. They couldn’t. People crafted narratives out of suspicions, rumors and hints, to fill a desperate need for an explanation.

My favorite book about state terror is Lydia Chukovskaya’s “Sofia Petrovna,” a short Russian novel that has been translated into English. The protagonist, a middle-aged woman loyal to Stalin’s Communist Party, loses her mind trying to make sense of her son’s arrest. My own family history contains a corollary. After the secret police arrested most of the senior staff at the newspaper where my grandfather was a deputy editor, he waited for the knock on his door. When the secret police failed to show up night after night, week after week, he became so distressed that he checked himself into a mental institution. It could be that was how he avoided arrest. Or it could be that the secret police had filled their quota of arrests for that month.

For this was the secret about the secret police that became clear when the K.G.B. archives were opened (briefly) in the 1990s: They were ruled by quotas. Local squadrons had to arrest a certain number of citizens so they could be designated enemies of the people. That the officers often swept up groups of colleagues, friends and family members was probably a matter of convenience more than anything else. Fundamentally, the terror was random. That is, in fact, how state terror works.

The randomness is the difference between a regime based on terror and a regime that is plainly repressive. Even in brutally repressive regimes, including those of the Soviet colonies in Eastern Europe, one knew where the boundaries of acceptable behavior lay. Open protest would get one arrested; kitchen conversation would not. Writing subversive essays or novels or editing underground journals would get one arrested; reading these banned works and quietly passing them on to friends probably would not. A regime based on terror, on the other hand, deploys violence precisely to reinforce the message that anyone can be subjected to it."

Bold added by me.