I slept through the whole thing. But a few minutes later, I stirred and came out of the bedroom to use the bathroom. At once I heard, “Freeze! Put your hands where I can see them!” (That, at any rate, was the gist of what I heard.) I will never forget seeing two officers, guns drawn, confronting me in the den.

It was a scary moment for me. But it must also have been terrifying for them: After loudly announcing themselves, they had moved into what might be a crime in progress to find a man walking around in the half-darkness.

Fortunately, I was too tired to be jumpy or loud. I slowly raised my hands and echoed Eddie Murphy’s immortal words in Trading Places: “Is there a problem, officers?”

Had I reacted differently; had I mistaken the police for burglars themselves; had I had a firearm in the house; or had I been a different person—one perceived by police in the dim light as in some way threatening—I would be dead. And I doubt that anyone would have said the police acted unreasonably.

I owe my life to a mixture of police professionalism and blind luck.

The lessons I draw from this are complex. I think that most police genuinely do not want to use deadly force. But I also think that, in a heavily armed and violent society, any encounter between police and the public is fraught with tension and ambiguity, and can easily go wrong. I don’t know whether Chief Justice John Roberts has ever had a pistol pointed at him by a police officer. I tend to doubt it. I sort of wish that he and the other members of the Supreme Court had found themselves, at least once, in a police encounter that could have gone sideways so easily.

If they had, I suspect, they might not be as cavalier about the problems of motorists stopped by police because of a “reasonable mistake of law.” The holding of Monday’s opinion in Heien v. North Carolina was that a police officer may stop a citizen and question him or her on “reasonable suspicion” of violating the law—even when the “law” the officer is enforcing turns out not to exist.

The facts of Heien are that a North Carolina sheriff’s deputy decided that a passing car was suspicious. The driver, he decided, seemed “very stiff and nervous” because he was looking straight ahead and holding his hands at the recommended positions on the wheel. (I am sure there was no connection, but the driver was also a Latino in an overwhelmingly white county.) The deputy followed the car, seeking a reason to make a stop, until the driver put on the brakes for a red light. One of the two brake lights was out. The deputy pulled over the car for the broken brake light and questioned both the driver and the owner, who had been sleeping in the back seat. Eventually he got permission to search the car, found cocaine, and arrested both men. A fairly open-and-shut case—except that, a state appeals court decided, North Carolina law only requires one working brake light. The “offense” leading to the stop was no more illegal than hanging a pine tree air freshener from the rear-view mirror.