Whether restrictions on publications sent into a prison are governed by the Procunier v. Martinez standard or the Turner v. Safley reasonableness standard.
Holding
They are governed by Turner's standard: a regulation is valid if it is reasonably related to legitimate penological interests.
Reasoning
The Court distinguished outgoing personal correspondence, which was the central concern of Martinez, from incoming publications. Outgoing letters ordinarily present more predictable and less serious risks to prison order; prohibited material such as escape plans, extortion threats, or plans for criminal activity can more readily be identified. Martinez therefore could require a closer fit between regulation and asserted interest in that setting.
Incoming publications create different and more substantial institutional concerns. Material brought into a prison may circulate among inmates, foster coordinated disruption, reveal or be perceived to reveal an inmate's political, sexual, or gang affiliations, and thereby provoke conflict. Prison officials need substantial discretion to assess those risks under the conditions of a particular institution at a particular time.
Turner supplies that needed flexibility. Its reasonableness inquiry recognizes both that prisoners and outside publishers retain First Amendment interests and that courts are poorly positioned to second-guess the difficult security judgments of prison administrators. The Court therefore limited Martinez to regulations governing outgoing correspondence and held that incoming publications are subject to Turner.