ABA Litigation Annual Conference, April 20-23, 2005:

Taming the Hydra-headed Monster: Fighting Cases On Multiple Fronts

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II. IMPACT OF CLAIM CONSTRUCTION RULING

When a federal district court issues claim construction rulings after a Markman proceeding, that ruling

may have a binding effect on proceedings in another federal district court involving the same patent

claim if the requirements of issue preclusion (also called collateral estoppel) are met. Typically, the

crucial factors in determining whether the first Markman ruling will preclude the patentee from

arguing a different claim construction in the other action are whether the court’s ruling was essential to

a “final judgment,” and whether the patentee had a full and fair opportunity to litigate the issue.

Settlement following an adverse claim construction presents an especially tricky trap for the unwary,

as some courts have held that such Markman rulings have preclusive effects on subsequent litigation,

while others have refused to bind the patentee; the law on this issue is currently unclear. A claim

construction approved or made by the Court of Appeals for the Federal Circuit may be binding even

against nonparties under the principles of stare decisis. Even where neither issue preclusion nor stare

decisis applies, the second court may find the prior ruling persuasive, or at least instructive. Therefore,

the patentee should consider the potential impact on future litigation involving other infringing

products and other defendants, when making strategic decisions concerning the timing and scope of

Markman hearings, and in settlement following an adverse claim co