The State Action Doctrine

State action is a constitutional "gatekeeping" requirement. The Fourteenth Amendment (and most constitutional provisions enforced through § 1983) constrain governmental conduct, not purely private conduct. Section 1983 uses different words - liability attaches only to a person who acts "under color of" state law - but in most cases the two inquiries track each other. Put simply, if conduct counts as "state action" for constitutional purposes, it will usually satisfy § 1983's "under color of law" requirement, and if it does not, it usually will not. The overlap is not perfect, and the cases in this unit show why: sometimes "under color" focuses on misuse of official authority by someone who is plainly a state official, while "state action" disputes often arise because the defendant is nominally private, and the question is whether the challenged conduct is fairly attributable to the state. 

Although this unit appears in the chapter on claims against state officials, the doctrine is not limited to traditional, on-duty state actors. State action principles matter whenever a plaintiff seeks to enforce constitutional limits against a defendant who looks private, hybrid, or outsourced, including private contractors (entities) performing governmental functions, private parties acting jointly with officials, and entities operating within heavily regulated or state-created systems.

The same analytic frame carries over to constitutional claims that are not brought through § 1983, including claims against federal officials and federal instrumentalities (typically litigated through different vehicles). The through-line is generally attributino - when, and why, the Constitution treats the challenged conduct as governmental conduct, regardless of the defendant's label.