A Bivens action generally refers to a lawsuit for damages when a federal officer who is acting in the color of federal authority allegedly violates the U.S. Constitution by federal officers acting.
Burden of Proof
The plaintiff in a Bivens action must prove that a constitutionally protected right has been violated by the federal officers.
The term “Bivens action” comes from Bivens v. Six Unknown Named Agents, 403 U.S. 388 (1971), in which the Supreme Court held that a violation of one’s Fourth Amendment rights by federal officers can give rise to a federal cause of action for damages for unlawful searches and seizures.
There are some exceptions to Bivens actions.
In Nixon v. Fitzgerald, 457 U.S. 731 (1982), the Supreme Court held that the President of United States is entitled to absolute immunity from Bivens actions.
In Butz v. Economou, 438 U.S. 478 (1978), the Supreme Court found that federal officials engaged in adjudicatory functions for an administrative agency within the Executive Branch are entitled to absolute immunity from damages for their judicial acts.
For more on a Bivens action, see this Northwestern University Law Review article, this University of Pennsylvania Law Review article, and this Cornell Law Review article.