“Any constitutional violation in Defendants’ current response to the COVID-19 crisis is different, in both nature and degree, from the violations underlying the 2009 population cap order,” the court’s decision said. “That order was never intended to prepare Defendants to confront this unprecedented pandemic. Nor could it have, given that the entire world was unprepared for the onslaught of the COVID-19 virus.”

As of Saturday, there were 13 confirmed cases of the virus in California prisons, but doctors have said the outbreak could rampage through jails and prisons because of the tight quarters as well as communal meals, showering and other activities.

The new court ruling noted that California officials are carrying out a plan to cut the prison population by 6,500 to mitigate the threat from the virus. And the judges encouraged the state officials to do more. “We urge them to leave no stone unturned,” the judges wrote.

The decision also said the judges took “no satisfaction” in turning aside — at least for now — what they called an “important question” of whether California’s actions to address the pandemic were sufficient to meet constitutional standards. The 2009 cap was ordered to address chronic failures to provide adequate medical care and mental health services to prisoners.

Mueller wrote separately on Saturday to say she disagreed with her colleagues that the virus outbreak was an “entirely distinct” issue from the health care concerns that fueled the earlier litigation. She noted that experts involved in the case more than a decade ago discussed the dangers of contagious disease among an overcrowded prison population.

“I am inclined to think this court retains broad equitable powers that might permit some reconsideration of the current cap in light of the unprecedented exigent circumstances here,” she wrote.

However, Mueller ultimately agreed with her colleagues that the law requires lawyers for the prisoners to approach individual District Court judges for relief first and also allows the state some period to make changes before releases are ordered.