jus tertii (j[schwa]s t[schwa]r-shee-I), n. [Latin]

1. The right of a third party. [Cases: Action 13; Federal Civil Procedure 103.

4. C.J.S. Actions §§ 57–63.]

“[N]o defendant in an action of trespass can plead the jus tertii — the right of possession outstanding in some third person — as against the fact of possession in the plaintiff.” R.F.V. Heuston, Salmond on the Law of Torts 46 (17th ed. 1977).

2. The doctrine that, particularly in constitutional law, courts do not decide what they do not need to decide.“Jus tertii … says nothing about the nature of legal argument on the merits of a case once formed, but as a symbol for the separability of cases is a useful term of art. Translated, however, it reads ‘right of a third person.’ It may once have been associated with a presumption of common-law jurisprudence that one cannot be harmed by an action that achieves its effect through effects upon others, cannot be ‘indirectly’ harmed.” Joseph Vining, Legal Identity 120 (1978).