Where the facts are sufficiently clear, res judicata or abuse of process may be suitable for determination as a preliminary issue, potentially avoiding a full trial.
Res judicata – literally, a “matter adjudged” – expresses a fundamental principle of civil justice: a dispute finally determined should not ordinarily be litigated again. The doctrine protects legal certainty, prevents inconsistent judgments, shields parties from repeated proceedings and preserves judicial resources. In commercial litigation, it can determine whether an action proceeds at all.
Its application is more nuanced than saying that “the matter has already been decided”. A later action may repeat the same cause of action, seek to reopen an issue decided earlier, or advance a claim that was never decided but should have been raised in the first proceedings. Each situation engages a different, although overlapping, rule.