Whether prison regulations that burden inmates' religious exercise are governed by the general Turner reasonableness test or by a heightened requirement that prison officials prove no reasonable accommodation is possible.
Holding
They are governed by the Turner test: a prison regulation is valid if it is reasonably related to legitimate penological interests.
Reasoning
Prisoners retain First Amendment protections, including the right to free exercise of religion, but incarceration necessarily limits many liberties. Those limits may be justified by valid penological objectives such as institutional security, order, deterrence, and rehabilitation. Because prison administrators bear primary responsibility for running difficult and potentially dangerous institutions, courts must give appropriate deference to their professional judgments.
The Court reaffirmed Turner v. Safley, decided the same Term: when a prison regulation impinges on a constitutional right, the regulation need only be reasonably related to legitimate penological interests. This standard permits officials to anticipate security problems and develop workable solutions without courts improperly managing prisons through detailed decrees.
The Third Circuit erred by requiring officials to prove that no reasonable way existed to accommodate the inmates' religious practice without causing genuine security problems. Although possible accommodations are relevant to reasonableness, Turner does not require prison officials to identify and disprove every conceivable alternative. Putting that burden on officials would insufficiently respect prison administrators' judgments.