The Court of Appeals for the Federal Circuit was established in 1982 with a mandate to bring uniformity to patent law. In service of that goal, the Federal Circuit ruled in 1998, and reaffirmed in an en banc decision last year, that a central issue in patent litigation, claim construction — the interpretation of the meaning of terms in patent claims — is a question of law, to be reviewed without deference on appeal.

But on January 20, in Teva Pharma­ceuticals USA v. Sandoz, the U.S. Supreme Court reversed the Federal Circuit and significantly modified that rule, holding that factual findings made by a trial court during claim construction must be reviewed deferentially on appeal, not on a de novo basis.

Teva can be seen as one of a number of Supreme Court rulings trimming back the discretion of the Federal Circuit and rejecting Federal Circuit holdings that established special procedural rules for patent cases.