A civil conspiracy is a legal doctrine under civil law that imposes liability on multiple actors who jointly participate in an unlawful scheme that causes harm to another party. The doctrine does not require that each conspirator personally commit the underlying wrongful act; rather, liability arises from the agreement to participate in the scheme and the acts taken to advance it. Civil conspiracy is commonly defined as: An agreement between two or more persons to accomplish an unlawful objective, or to accomplish a lawful objective by unlawful means, resulting in damages to another party.
The cause of action typically requires proof of several elements:
Agreement: Two or more persons reached a tacit or explicit understanding to pursue a common plan.
Unlawful Objective or Unlawful Means: The conspirators intended to commit a tort, violate a legal duty, or accomplish an otherwise lawful objective through illegal acts.
Overt Act in Furtherance of the Conspiracy: At least one conspirator committed an act to advance the scheme.
Resulting Damages: The plaintiff suffered injury caused by the acts undertaken in furtherance of the conspiracy.
Civil conspiracy therefore functions as a liability-expanding doctrine, allowing a plaintiff to hold all participating actors responsible for the wrongful acts committed by any one conspirator.
Civil conspiracy has several distinctive features:
Derivative Liability - Civil conspiracy is not usually an independent tort. It depends on an underlying wrongful act (fraud, civil rights violations, abuse of authority, etc.).
Joint and Several Liability - Each conspirator can be held responsible for the full amount of damages caused by the conspiracy.
Tacit Agreement Is Sufficient - A formal written agreement is not required. Courts often infer conspiracy from coordinated conduct, patterns of behavior, or circumstantial evidence.
Knowledge and Participation - Each participant must have knowledge of the scheme and intentionally participate in it.
In federal civil rights litigation, civil conspiracy claims are often brought under 42 U.S.C. §1983 or 42 U.S.C. §1985 when government actors coordinate to deprive individuals of constitutional rights. Courts generally require proof that:
two or more persons acted in concert,
they intended to deprive a person of a constitutional right,
and an overt act caused injury.
This doctrine is frequently invoked in cases involving coordinated misconduct among law enforcement officers, prosecutors, or government officials.
Civil conspiracy can also describe institutional misconduct, where organizational actors collectively participate in a pattern of wrongdoing or concealment.
For example, allegations in litigation involving Los Angeles County juvenile facilities asserted that officials were repeatedly informed of abuse but failed to act while maintaining a façade of normal operations, creating an environment that allegedly protected serial abusers.
When such patterns involve coordinated concealment, intimidation of witnesses, or suppression of complaints, plaintiffs often argue that the conduct constitutes a civil conspiracy.
Courts have addressed civil conspiracy in numerous cases, including:
Halberstam v. Welch, 705 F.2d 472 (D.C. Cir. 1983) — influential articulation of civil conspiracy liability and aiding-and-abetting principles.
Adickes v. S.H. Kress & Co., 398 U.S. 144 (1970) — conspiracy between state actors and private parties under civil rights law.
Dennis v. Sparks, 449 U.S. 24 (1980) — private parties conspiring with a judge may be liable under §1983.
Prosser & Keeton, Law of Torts, §46 (Civil Conspiracy).
Restatement (Second) of Torts §876 (Persons Acting in Concert).
U.S. Department of Justice Civil Rights Division materials on §1983 and §1985 conspiracies.
Wright & Miller, Federal Practice and Procedure, Civil Rights Litigation.
Civil conspiracy may be summarized as: A coordinated agreement among multiple actors to commit a wrongful act or violate a legal duty, where each participant becomes legally responsible for the harm caused by the collective scheme.