Last week Texas killed Marvin Wilson—the 484th person the Lone Star State has executed since the death penalty was reinstated in 1977. Wilson’s execution became national news because he was mentally retarded: his IQ had been measured at 61. He was also my client.

When I first met Wilson nearly seven years ago, he was soft spoken, almost shy. His reading and writing skills were around the level of my son’s, who was 5 at the time. He told me getting convicted of murder was good because it gave him an opportunity to learn a lot of things. I asked him what he meant. He said, “You know, how to live on your own and things.”

In 2002 the Supreme Court ruled in Atkins v. Virginia that it was unconstitutional to execute the mentally retarded. You might think that would have ended the execution of the mentally retarded, but you would be wrong.

Why? Because Texas executes the mentally retarded anyway, and the federal courts don't seem to care. In a 2004 decision the Texas Court of Criminal Appeals issued a decision called Ex parte Briseno, which basically said it is OK to execute people who are mentally retarded, so long as their retardation is “mild.” That is not what the Supreme Court said in Atkins. In fact, it is pretty much the opposite of what the Supreme Court said. Without putting too fine a point on it, doing the opposite of what the Supreme Court says is what is known as being lawless. Which raises the question: If you do something over and over again, and court after court appears not to care, is it still lawless?

Let's not dance on the head of that pin just yet. Instead, some background: Wilson’s legal team, which included five lawyers as well as five law students from the University of Houston, where I teach, asked both state and federal courts to halt his execution. We had several arguments, but the one incontestable proposition was that Wilson was mentally retarded. Five IQ tests and testimony from numerous witnesses proved it. During the state court litigation, the only psychological expert to express an opinion testified that he was retarded. The state neither undermined his testimony nor had its own expert dispute that claim. So if the Supreme Court says you cannot executed the mentally retarded, and the only expert to testify says Marvin Wilson was retarded, how is it possible he got executed? Welcome to Texas!

Here’s an interesting statistic: nationwide, about four in 10 death-row inmates raising Atkins claims have prevailed. But in Texas, that number is 1 in 4. One possible explanation for the disparity is that Texas does not send as many mentally retarded people to death row. But I've been a death penalty lawyer for more than 20 years, and I can tell you firsthand that explanation doesn’t fly.

Which leaves the second, and true, explanation: Texas has found a way to circumvent the Constitution, and neither the U.S. Court of Appeals for the Fifth Circuit nor the Supreme Court appears to care. That might surprise you, if you believe in that thing called the rule of law, but death-penalty lawyers in Texas aren't surprised, because this has happened before.

In 1989 the Supreme Court handed down a decision called Penry v. Lynaugh. The case involved an inmate, Johnny Paul Penry, with an IQ in the mid-50s. The court in that case declined to prohibit the execution of the mentally retarded, but it did say that the Texas system was fundamentally broken, because juries had no way to spare certain defendants from death, even if they believed those defendants should be sentenced to life in prison.

I gave an interview after that decision saying its consequences would be dramatic; I predicted scores of death-row inmates in Texas would benefit. But I was young and naive. I did not realize Texas would ignore the decision, and that the Fifth Circuit and the Supreme Court wouldn't care. But that is precisely what happened. Over the next 15 years, more than 100 inmates with powerful so-called Penry claims got executed. They argued their juries had not had any way to sentence them to life in prison rather than death, even if those juries had wanted to spare them. Yet neither the Texas courts nor the Fifth Circuit nor even the Supreme Court did a thing. Finally, a decade and a half later, after nearly everyone with a Penry claim had already been executed, the Supreme Court broke its silence and issued a searing rebuke to both the state court and the Fifth Circuit, saying they were being unfaithful to the ruling in Penry.

The rebuke was treated as a big deal by the national media. Overlooked was the fact that the Supreme Court knew what had been going on in Texas all along. Yet the justices did nothing, and by the time they decided to say something, they knew full well that virtually every inmate whose life had depended on the faithful application of the Penry decision had already been buried.

So why doesn’t the Supreme Court make a bigger stink when its own rulings aren’t followed? Isn’t that its core purpose, after all? To lay down the law of the land for all other courts?

There are at least two explanations for why this happens. One is that over the past quarter century or so, the federal courts have taken a largely hands-off approach to the administration of criminal justice. They let the states do what they want. In part this attitude is required by a federal law enacted during the Clinton Administration, but more fundamentally, it dates to an ideological shift in the mid and late 1980s that resulted in a greater judicial indifference to legal violations in criminal cases. When a murder trial in China takes less than a day, or Islamists in Mali chop of the hand of a condemned thief, we look down our noses at the crudity of those legal regimes. But ignoring the rights of the accused in a stadium filled with screaming hordes is not all that different from disregarding the rights of an accused in a courtroom full of reporters.

Another factor is that the Supreme Court is a fundamentally conservative institution. Every once in a while, it will do something dramatic—strike down racial integration, uphold a woman's right to control her own body, prohibit the execution of the retarded—but those decisions are remarkable because they are exceptional. And more important, after nearly every controversial decision, the justices seem to have a Lady Macbethian urge to wash their hands of what they have done. They back away and hem and haw and leave it to the lower courts to implement their decisions. But if the lower courts balk, the decision does not get implemented.

It obviously doesn’t happen all the time—the mere prospect of being rebuked by the Supreme Court probably makes lower courts reluctant to be altogether contemptuous of their rulings. But it happens often enough to be worrisome, and what’s worse, it happens mostly in cases involving the powerless.

The weeks leading up to Wilson’s execution involved complicated legal issues, but we gave up trying to explain the details to him. He knew there was activity, of course, but he was simply incapable of understanding it.

The fact of his mental deficiency may not matter to you, since he was unquestionably guilty of participating in a crime that included a murder. You might say that even the retarded should know not to kill. I could argue with you that you are wrong, but if you also respect the rule of law, you would have to acknowledge that, so long as the Supreme Court has the final say on what the Constitution means, the states are not permitted to execute the retarded. That they do anyway, and do so with impunity, reveals more about our attitude toward the rule of law than our attitude toward crime.