Also known as: principal actions · main action · primary action
Written by attorneys · grounded in primary & secondary sources — see below
A plaintiff's primary claim against one or more defendants contained in the original or validly amended pleading.
Premier Manufacturing sued Prism Analytics for breach of a supply contract. Patriot Insurance moved to intervene asserting a defense that turned on the same contract interpretation issue. The court evaluated whether the defense shared a common question with the principal action before granting permissive intervention.
RedRiver Distributors sued NovaPharm for lost profits under a supply contract. NovaPharm impleaded PackRight for packaging errors. The pharmacies sought to intervene against PackRight with claims arising from the same supply failure that formed the principal action.
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The City of Norwood filed an eminent domain action against Horney to acquire property. Horney sought an injunction to halt the taking while the principal action proceeded. The court considered whether the injunction was ancillary to preserving the subject matter of the principal action.
Edmondson Oil obtained a writ of attachment against Lugar's property before filing the principal action on the underlying debt. Lugar challenged the attachment as state action under the Fourteenth Amendment. The principal action later proceeded to judgment after the attachment dispute was resolved.
Family Finance obtained a prejudgment garnishment of Sniadach's wages. Sniadach challenged the procedure as violating due process before the principal action on the debt reached judgment. The Court examined whether the garnishment could stand apart from the principal action.
A shareholder filed a derivative suit against Beneficial Industrial Loan Corp. The corporation moved to require the plaintiff to post security for costs. The Court considered whether the security rule applied in the federal principal action under diversity jurisdiction.
The principal action is the plaintiff's original claim against the defendant or defendants named in the complaint. A crossclaim is asserted between coparties and must arise from the same transaction or occurrence as the principal action. A third-party claim seeks derivative liability from a nonparty who may be liable for all or part of the principal action.
The principal action supplies the original jurisdiction that allows federal courts to entertain related claims under supplemental jurisdiction. Ancillary or pendent claims are evaluated by whether they form part of the same case or controversy as the principal action. Limitations in diversity cases restrict supplemental jurisdiction over certain claims by plaintiffs against parties joined under Rules 14, 19, 20, or 24.
A party may seek permissive intervention when it has a claim or defense that shares a common question of law or fact with the principal action. The motion must be timely and the court must weigh undue delay or prejudice to the existing parties. Intervention does not require an unconditional statutory right or an interest that would support intervention of right.
…might be adversely affected if they could not air their claims in an ongoing federal-court action. Given jurisdiction over the principal action, federal courts entertained certain matters deemed ancillary regardless of the citizenship of the parties or the amount in controversy. Mine Workers v. Gibbs , 383 U. S. 715 (1966), the…