The death penalty is at one and the same time the simplest and the most complicated legal issue in America. Simple because it’s ancient, because it satisfies our most basic moral intuitions, and because it’s founded on the most fundamental principle of justice: an eye for an eye. Complicated because it has spawned a Kafka-esque area of law, where every case pin-balls from court to court with a cascading number of legal claims until no one involved has much idea what is going on.

In a perfect world, the complexity and the simplicity would balance each other out. Prosecutors would only pursue the sentence with truly egregious crimes and rock-solid evidence, juries would only hand it down when they agreed with complete certainty, and judges would only affirm it when the law and the facts remained crystal-clear after years of appellate review.

As we all know, this is not a perfect world.

The execution of Humberto Leal Garcia last Thursday underscores the imperfection. Garcia’s case, as with all death penalty cases, involved a host of complicated issues. The one that garnered the most attention was its international dimension. Garcia was a Mexican citizen arrested in Texas for the heinous rape and murder of a young woman. Under international law, he had a clear right to speak with his country’s consulate, which would almost certainly have provided him competent lawyers, who would in turn almost certainly have managed to save their client’s life, if not his liberty. He wasn’t allowed to, and, after the U.S. Supreme Court rejected his final appeal by the thinnest of margins, he died.

As difficult as it might be to appreciate, Garcia’s death does say at least one positive about America: it says that ...