Constitutional Law
State Action Doctrine
Definition
The state action doctrine limits constitutional protections to actions taken by the government or its agents, not private actors. The Fourteenth Amendment's equal protection and due process guarantees apply only when there is sufficient governmental involvement. Courts have found state action through the public function test (when a private entity performs a traditional and exclusive government function), the entanglement/nexus test, and the coercion test. The doctrine marks the boundary between public and private spheres.
Example
A private company refuses to serve a customer based on race. Unless the company is performing a public function or acting under government coercion, there is no state action and no constitutional violation.