In the 1971 case of Mancusi v. Stubbs, the U.S. Supreme Court ruled in favor of a prisoner's right to receive uncensored mail from his attorney. Robert Stubbs, an inmate at Attica Prison in New York, claimed that prison officials violated his Sixth Amendment rights by reading correspondence between him and his lawyer before it reached him. The court held that while prisons may inspect mail for contraband or other security risks, they cannot read legal correspondence without violating inmates' constitutional rights to counsel and due process under law. This decision reinforced prisoners' limited but important protections under the Constitution.

In the case of Mancusi v. Stubbs, Justice Harlan dissented from the majority opinion. He argued that prisoners should not be denied their constitutional rights unless there was a compelling reason related to prison administration or discipline. Harlan believed that in this case, no such compelling reason existed for denying Stubbs his right to possess certain publications and personal papers in his cell. The justice also disagreed with the majority's view on how courts should review decisions made by prison officials; he felt that judges were capable of making these determinations without overstepping their bounds or interfering with prison management. Furthermore, he criticized the court's decision as being too deferential towards prison authorities and failing to adequately protect inmates' constitutional rights.