In 1925, a young American physicist was doing graduate work at Cambridge University, in England. He was depressed. He was fighting with his mother and had just broken up with his girlfriend. His strength was in theoretical physics, but he was being forced to sit in a laboratory making thin films of beryllium. In the fall of that year, he dosed an apple with noxious chemicals from the lab and put it on the desk of his tutor, Patrick Blackett. Blackett, luckily, didn’t eat the apple. But school officials found out what happened, and arrived at a punishment: the student was to be put on probation and ordered to go to London for regular sessions with a psychiatrist.

Probation? These days, we routinely suspend or expel high-school students for doing infinitely less harmful things, like fighting or drinking or taking drugs—that is, for doing the kinds of things that teen-agers do. This past summer, Rhett Bomar, the starting quarterback for the University of Oklahoma Sooners, was cut from the team when he was found to have been “overpaid” (receiving wages for more hours than he worked, with the apparent complicity of his boss) at his job at a car dealership. Even in Oklahoma, people seemed to think that kicking someone off a football team for having cut a few corners on his job made perfect sense. This is the age of zero tolerance. Rules are rules. Students have to be held accountable for their actions. Institutions must signal their expectations firmly and unambiguously: every school principal and every college president, these days, reads from exactly the same script. What, then, of a student who gives his teacher a poisoned apple? Surely he ought to be expelled from school and sent before a judge.

Suppose you cared about the student, though, and had some idea of his situation and his potential. Would you feel the same way? You might. Trying to poison your tutor is no small infraction. Then again, you might decide, as the dons at Cambridge clearly did, that what had happened called for a measure of leniency. They knew that the student had never done anything like this before, and that he wasn’t well. And they knew that to file charges would almost certainly ruin his career. Cambridge wasn’t sure that the benefits of enforcing the law, in this case, were greater than the benefits of allowing the offender an unimpeded future.

Schools, historically, have been home to this kind of discretionary justice. You let the principal or the teacher decide what to do about cheating because you know that every case of cheating is different—and, more to the point, that every cheater is different. Jimmy is incorrigible, and needs the shock of expulsion. But Bobby just needs a talking to, because he’s a decent kid, and Mary and Jane cheated because the teacher foolishly stepped out of the classroom in the middle of the test, and the temptation was simply too much. A Tennessee study found that after zero-tolerance programs were adopted by the state’s public schools the frequency of targeted offenses soared: the firm and unambiguous punishments weren’t deterring bad behavior at all. Is that really a surprise? If you’re a teen-ager, the announcement that an act will be sternly punished doesn’t always sink in, and it isn’t always obvious when you’re doing the thing you aren’t supposed to be doing. Why? Because you’re a teen-ager.

Somewhere along the way—perhaps in response to Columbine—we forgot the value of discretion in disciplining the young. “Ultimately, they have to make right decisions,” the Oklahoma football coach, Bob Stoops, said of his players, after jettisoning his quarterback. “When they do not, the consequences are serious.” Open and shut: he sounded as if he were talking about a senior executive of Enron, rather than a college sophomore whose primary obligation at Oklahoma was to throw a football in the direction of young men in helmets. You might think that if the University of Oklahoma was so touchy about its quarterback being “overpaid” it ought to have kept closer track of his work habits with an on-campus job. But making a fetish of personal accountability conveniently removes the need for institutional accountability. (We court-martial the grunts who abuse prisoners, not the commanding officers who let the abuse happen.) To acknowledge that the causes of our actions are complex and muddy seems permissive, and permissiveness is the hallmark of an ideology now firmly in disgrace. That conservative patron saint Whittaker Chambers once defined liberalism as Christ without the Crucifixion. But punishment without the possibility of redemption is worse: it is the Crucifixion without Christ.

As for the student whose career Cambridge saved? He left at the end of the academic year and went to study at the University of Göttingen, where he made important contributions to quantum theory. Later, after a brilliant academic career, he was entrusted with leading one of the most critical and morally charged projects in the history of science. His name was Robert Oppenheimer.