Jus Tertii

Jus Tertii refers to a legal principle wherein a party may argue that a third party has rights that affect their own legal standing or claim in a case. This principle often arises in property law and litigation concerning the enforcement of rights or defenses against claims made by the state or other entities.

The principle originates from Roman law, where third-party rights were acknowledged in disputes involving ownership and possession. Its application has been refined over the centuries through common law and statutory developments.

In modern law, Jus Tertii is pertinent in situations such as landlord-tenant disputes, where the landlord may invoke the rights of a third-party entity. Courts may also consider the rights of third parties when adjudicating matters affecting those not directly involved in the litigation, particularly in constitutional law and civil rights cases.

• A tenant (who lacks ownership rights) arguing that a landlord's eviction is improper due to a third party's prior occupancy rights.
• In constitutional law, an individual citing Jus Tertii to argue that a law violates the rights of a third party not present in the case.

• Lujan v. Defenders of Wildlife, 504 U.S. 555 (1992)