MBE Rules · Civil Procedure

Interstate Preclusion

28 U.S.C. §1738 (judgments)

The rule

Courts must give a judgment the same preclusive effect it would receive in the rendering jurisdiction; federal courts sitting in diversity apply the preclusion law of the state where the rendering federal court sat (Semtek).

In plain English

Interstate preclusion means that if a court in one state issues a judgment, other states must treat that judgment as valid and enforceable according to the laws of the state where the judgment was made. This is especially important in federal courts sitting in diversity, which must apply the preclusion laws of the state where the federal court is located.

Worked example

A plaintiff wins a breach of contract case in a California state court. Later, the same plaintiff tries to sue the same defendant for the same breach in a New York federal court. The New York court will recognize the California judgment and dismiss the case based on preclusion, as California law prevents relitigation of the same issue.

Memory hook

What happens in one state, stays in that state—at least in court!

The trap

Exams may confuse students by presenting scenarios where the judgment is from a different jurisdiction, leading students to misapply preclusion principles. Watch out for details about the rendering jurisdiction's laws.

How examiners test it

Questions often involve a fact pattern where a judgment from one state is challenged in another, requiring students to identify the applicable preclusion law and its effects.

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