12 Multiple Claims and Parties; Intervention

A party may assert any claim substantially connected to the subject matter of the proceeding against another party or against a third person subject to the jurisdiction of the court.

A person having an interest substantially connected with the subject matter of the proceeding may apply to intervene. The court itself, or on motion of a party, may require notice to a person having such an interest, inviting intervention. Intervention may be permitted unless it would result in unreasonable delay or confusion of the proceeding or otherwise unfairly prejudice a party. Forum law may permit intervention in second-instance proceedings.

When appropriate, the court should grant permission for a person to be substituted for, or to be admitted in succession to, a party.

The rights and obligations of participation and cooperation of a party added to the proceeding are ordinarily the same as those of the original parties. The extent of these rights and obligations may depend upon the basis, timing, and circumstances of the joinder or intervention.

The court may order separation of claims, issues, or parties, or consolidation with other proceedings, for fair or more efficient management and determination or in the interest of justice. The authority should extend to parties or claims that are not within the scope of these Principles.