In pari causa

IN PARI CAUSA. In an equal cause. It is a rule that when two persons have equal rights in relation to a particular thing, the party in possession is considered as having the better right: in pari causa possessor potior est. Dig. 50; 17, 128; 1 Bouv. Inst. n. 952.

A Law Dictionary, Adapted to the Constitution and Laws of the United States. By John Bouvier. Published 1856.