WASHINGTON — Michael Johnson, a prisoner in Illinois, suffered from what the corrections system acknowledged was profound mental illness. That made him hard to handle, and prison officials responded by putting him in solitary confinement. Total isolation, in a windowless cell, made things worse.

He hallucinated, compulsively picked at his skin and smeared himself with his own waste. He was often on suicide watch. And he violated countless prison rules, disobeying guards’ orders, spitting at them and damaging property.

As a punishment for those violations, prison authorities took away his one sliver of solace: the hour of exercise that prisoners in solitary were generally afforded five days a week, typically in a small, secured cage outdoors.

The Supreme Court will soon decide whether to hear a case from Texas on a large question: whether prolonged solitary confinement is cruel and unusual punishment, which is banned under the Eighth Amendment.

But the justices may prefer to start with a narrower issue, raised in Mr. Johnson’s petition seeking Supreme Court review: Do prisoners in solitary have a constitutional right to regular outdoor exercise?

Most federal appeals courts have said the answer is yes.

Justice Anthony M. Kennedy, not long after he became a federal appeals court judge, wrote that prisoners in solitary confinement have a right to a little fresh air once in a while.

“Some form of regular outdoor exercise is extremely important to the psychological and physical well-being of the inmates,” he wrote in 1979 for a unanimous three-member panel of the U.S. Court of Appeals for the Ninth Circuit, in San Francisco. “It was cruel and unusual punishment for a prisoner to be confined for a period of years without opportunity to go outside except for occasional court appearances, attorney interviews and hospital appointments.”

On the Supreme Court, before his retirement in 2018, Justice Kennedy continued to criticize solitary confinement more generally. “Years on end of near total isolation exact a terrible price,” he wrote in a 2015 concurring opinion, noting that “common side effects of solitary confinement include anxiety, panic, withdrawal, hallucinations, self-mutilation, and suicidal thoughts and behaviors.”

Starting in 2013, prison officials punished Mr. Johnson for his misconduct by canceling his “yard privileges,” meaning his ability to exercise outdoors. The individual punishments lasted from 30 to 90 days, but they added up, amounting to about three years without that time, two of them consecutive.

Starting in 2013, prison officials punished Michael Johnson for his misconduct by canceling his “yard privileges.”Credit…Illinois Department of Corrections

During that time, he was allowed to leave his cell for a weekly 10-minute shower and, in theory, a single hour of exercise each month. That hour, his lawyers said, was frequently canceled.

All the while, Mr. Johnson, who was serving time for a home invasion and assault, was asking for a transfer to a mental-health unit. He sued prison officials in June 2016, saying that the prolonged denial of exercise had crossed a constitutional line. Two months later, the transfer was approved.

A divided three-judge panel of the U.S. Court of Appeals for the Seventh Circuit ruled that denying Mr. Johnson the ability to exercise for 90 days at time as punishment for serious misconduct did not violate the Eighth Amendment. “Nor is it,” Judge Diane S. Sykes wrote for the majority, “an Eighth Amendment violation to ‘stack’ such penalties.”

In dissent, Judge Ilana D. Rovner said there were at least two flaws in that reasoning. One was that Mr. Johnson suffered from “a deteriorating mental state that virtually ensured further rules violations, creating a self-perpetuating cycle.”

The other, she wrote, was that exercise “is an essential human need.” Drawing on a statement in a 1991 Supreme Court decision, she said exercise ranked with food and warmth as fundamental requirements in civilized societies.

Judge Rovner acknowledged that restrictions on exercise might be warranted to address security threats like the risk of an escape or an attack on others. But prison officials never justified the restrictions on those grounds. The denial of exercise, they said, was punishment, pure and simple.

Mr. Johnson, represented by the Roderick and Solange MacArthur Justice Center, asked the full Seventh Circuit to rehear his appeal. The court turned them down by a tie vote, with five judges in favor and five against.

Dissenting from the decision not to rehear the case, Judge Diane P. Wood said prison officials may no more deprive inmates of exercise than they may starve or torture them.

“No one is saying that a 24-hour deprivation, or even a deprivation lasting two or three weeks, automatically violates the Eighth Amendment, any more than one would say that the Constitution entitles Johnson to a state-of-the-art gym,” Judge Wood wrote. “But somewhere between three weeks and two years, the constitutional line is crossed.”

In their appeals court brief, prison officials conceded that “exercise is a basic human need, and its long-term denial may constitute cruel and unusual punishment.” But 90 days is not a long-term denial, the brief said, and “yard restrictions imposed because of prison rule violations should be considered individually, not ‘stacked’ and considered as one cumulative restriction.”

In any event, the brief added, quoting an earlier decision, Mr. Johnson “could still ‘engage in exercise in his cell such as push-ups, situps, jogging in place, and step-ups.’”

When Mr. Johnson’s lawyers asked the Supreme Court to hear his case, Johnson v. Prentice, No. 22-693, prison officials waived their right to file a brief. Last month, the court requested a response, which is due April 17.

In her dissent, Judge Wood urged the justices to pay heed. “The majority’s decision,” she wrote, “puts the Seventh Circuit at odds with many other courts and thus makes this case a suitable candidate for Supreme Court attention.”