Fed. R. Civ. P. 24(b)
Definition
A rule of the Federal Rules of Civil Procedure allowing a court to permit a person’s intervention in a case (1) if federal law provides a conditional right to intervene, (2) if the person’s claim or defense has a question of law or fact common to the matter, or (3) if a government official seeks to intervene based on a claim arising from a law, order, or regulation administered by such official.