Responsibility for Substantive Offenses Committed by Co-Conspirators (Pinkerton Liability) is a legal doctrine that holds a principal conspirator liable for any crimes committed by a co-conspirator in furtherance of the conspiracy. Pinkerton Liability stems from the Supreme Court decision in Pinkerton v. United States, 328 U.S. 640 (1946) and applies to all federal criminal conspiracies. Under the Pinkerton doctrine, a principal conspirator is liable for any crimes committed by a co-conspirator if the crime was “reasonably foreseeable” in furtherance of the conspiracy. The doctrine is premised on the idea that a person who joins a criminal conspiracy is responsible for the acts of any other conspirators and the harm that results from them. There are two types of responsibility for substantive offenses committed by co-conspirators under Pinkerton Liability: proximate cause and vicarious liability. Proximate cause is the legal standard that requires a person to have a “substantial connection” between their actions and the harms caused by another person in order to be held liable. Vicarious liability is the legal doctrine that holds one person responsible for the acts of another. Under Pinkerton Liability, a principal conspirator can be held criminally responsible for the acts of a co-conspirator if the acts were reasonably foreseeable and committed in furtherance of the conspiracy. The doctrine of responsibility for substantive offenses committed by co-conspirators applies to all federal criminal conspiracies and is a powerful tool for prosecutors in holding all members of a criminal organization accountable for their actions.