Definition - What does Compulsory Joinder mean?
Compulsory joinder refers to when a court finds that a party, or parties, must be added to a lawsuit. This need arises when a party, who is currently not a party to a lawsuit, is necessary and indispensable to the litigation of the lawsuit. In other words, if a court is being asked to determine the rights of a person or entity who is not named as a party to the lawsuit, then that person or entity must be joined in the lawsuit before the court will hear the case.
Compulsory joinder is also known as required joinder or mandatory joinder.
Justipedia explains Compulsory Joinder
Compulsory joinder is governed by Rule 19 of the Federal Rules of Civil Procedure. All states in the United States also have their own jurisdictional equivalent to this rule. While a necessary and indispensable party will always be joined if possible, the court has discretion, in equity and good conscience, to proceed with the lawsuit or to determine that the suit should be dismissed.
There are various instances when a compulsory joinder may be deemed necessary by the court. For example, if there are three parties that all assert a claim to a piece of land and the first party sues the second party, the third party will not be able to protect his alleged interest in the land if he or she is not made a party to the suit.