More than 200 inmates at Pelican Bay, California’s toughest prison, have spent over a decade locked in windowless 8-foot-by-12-foot cells for 22 hours or more a day. Dozens more have been in solitary confinement for 15 years — or even longer.

But in a ruling this week, a federal judge in Oakland, Calif., agreed to consider whether, as a lawsuit against the state’s corrections department maintains, holding prisoners in such prolonged isolation violates their rights under the Eighth Amendment.

Legal experts say that the ruling, which allows inmates at Pelican Bay who have been held in solitary confinement for more than a decade to sue as a class, paves the way for a court case that could shape national policy on the use of long-term solitary confinement.

“It seems that the judge is going to decide the broad policy questions involved here,” said Jules Lobel, a constitutional law professor at the University of Pittsburgh and the president of the Center for Constitutional Rights, which originally brought the suit on behalf of 10 inmates in the security housing unit at Pelican Bay. Without class-action status, any decision in the lawsuit could have been restricted only to those plaintiffs and not the broader policy.