The continued practice of indefinite solitary confinement is a failure of administration, whether the Supreme Court chooses to correct it or not. I say “failure” because it does not succeed in its stated aims. Solitary confinement fails to make prisoners less violent. It exacerbates mental illness in some prisoners and is the cause of it for many others; a recent study revealed that at present some 4,000 inmates suffering from mental illness are being held in solitary confinement in American prisons. In New Mexico, 64 percent of inmates who are mentally ill are in “the shoe.”

Solitary confinement is also something far more serious than an administrative failure. Putting men away in cells for weeks, months, and years at a time is a failure of the moral imagination, and a typically modern one. Unable to conceive of a fate worse than death for the very wicked, we have convinced ourselves that it is more merciful to torture a man for decades than to execute him swiftly.

Our wisest ancestors knew better.