Rule 24.01. Intervention as of Right
Upon timely motion any person shall be permitted to intervene in an action. (1) when a statute confers an unconditional right to intervene; or (2) when the movant claims an interest relating to the property or transaction which is the subject of the action and the movant is so situated that the disposition of the action may as a practical matter impair or impede the movant’s ability to protect that interest, unless the movant’s interest is adequately represented by existing parties; or (3) by stipulation of all the parties.
Click here for Advisory Commission Comments to Rules 24.01-24.05.