Blonder-Tongue Labs., Inc. v. University of Ill. Foundation, 402 U.S. 313 (1971), is a decision of the United States Supreme Court holding that a final judgment in an infringement suit against a first defendant that a patent is invalid bars the patentee from relitigating the same patent against other defendants. In so ruling, the Supreme Court overruled its 1936 decision in Triplett v. Lowell, which had required mutuality of estoppel to bar such preclusion, and held that the better view was to prevent relitigating if the plaintiff had had a full and fair opportunity to litigate the issue in question.
Background
The University of Illinois Foundation owned Isbell U.S. Patent No. 3,210,767, covering "Frequency Independent Unidirectional Antennas," which were used for transmission and reception of radio and television signals. The Foundation sued Winegard Co., an antenna manufacturer in Iowa, and the court held the patent invalid as obvious. On appeal, the Eighth Circuit affirmed the judgment in the Iowa case.
The Foundation also sued a customer of another antenna manufacturer, Blonder-Tongue, in Illinois. Blonder-Tongue intervened to defend its customer and filed a counterclaim for invalidity. The Illinois court held the patent valid and infringed, despite the contrary ruling in Iowa, because it disagreed with the conclusion that the Iowa court reached in the case against Winegard. Blonder-Tongue appealed to the Seventh Circuit, which upheld the ruling that the Isbell patent was valid and infringed.
Blonder-Tongue then appealed to the Supreme Court. Under prior law, a patentee was entitled to sue an alleged infringer, even though a different court had ruled the patent invalid: The second court was free to decide the second case on the basis of the evidence before it, irrespective of the first court's ruling, according to Triplett v. Lowell. The Supreme Court granted certiorari to decide the question, "Should the holding of Triplett v. Lowell, 297 U. S. 638, that a determination of patent invalidity is not res judicata as against the patentee in subsequent litigation against a different defendant, be adhered to?"—even though Blonder-Tongue had asked the Court to rule only on the merits of the patentee's infringement case.
Ruling of Supreme Court
Justice Byron White delivered the opinion of a unanimous Court that Triplett should be overruled and that patent owners should be entitled to only one bite at the apple, because the doctrine requiring mutuality of estoppel—that both parties must be bound by the prior judgment or neither party is bound—was contrary to public policy, at least in patent cases.
White began by noting that the doctrine allowing multiple litigation on a patent held invalid had been criticized, yet both parties' patent lawyers in this case were unwilling to ask for Triplett to be overruled. White quoted Blonder-Tongue's counsel as saying, "Though petitioners stand to gain by any such result, we cannot urge the destruction of a long-accepted safeguard for patentees merely for the expediency of victory." The Assistant Attorney General of the Antitrust Division, however, arguing for the Government as amicus curiae, urged the Court to overrule Triplett partially—to permit or preclude relitigating patents on a case-by-case fact-specific basis.
A preliminary question was whether it was proper for the Court to overrule Triplett when both party litigants were unwilling to urge its being overruled. Under intense questioning by the Court in oral argument, however, counsel for the accused infringer (who initially sought to argue that the patented antenna structure should have been held obvious over the prior art) receded to the position that in the particular circumstances of the case (the trial court had forced Blonder-Tongue to go to trial without its witnesses) the evidence from the Winegard case in Iowa should have been considered. No party argued for so-called in rem invalidity, and neither did the United States as amicus curiae. In the last few minutes of Blonder-Tongue counsel's rebuttal argument, Justice White asked him: "Petitioner decided finally to forego any request for reconsidering Triplett entirely or in any part? I had understood you previously say you would welcome a modification of it to some extent?" Counsel replied that, in a case in which a party had not been given the opportunity to present its witnesses, "it ought to be considered whether there ought to be an estoppel in a situation such this." In view of Blonder-Tongue's "change of attitude," the Court said, "we consider that the question of modifying Triplett is properly before us."