No case/controversy in US for threats of infringement made outside US on non-US patents

In Allied Mineral, 2017 U.S. App. LEXIS 17667, the CAFC addressed DJs in view of a threat of litigation from a foreign patent,

From the decision:



All of Stellar's conduct has been directed towards Allied's customers Ferro and Pyrotek, unrelated Mexican entities, and that contact was limited to Stellar's Mexican Patent and potentially infringing acts in Mexico. Stellar sent notice letters to the customers alone, and although Allied responded on behalf of its customers, Stellar never responded to Allied's letter. [*5] Stellar then sued only the customers, not the manufacturer. Stellar also limited its actions to Mexico. Stellar filed suit in Mexico, suing for infringement of a Mexican patent under Mexican laws. It has not threatened or alleged infringement of the '974 patent in the United States, much less filed suit. Stellar took no actions directed at Allied, no actions with regard to its '974 patent, and no actions under U.S. patent laws.

(...)

Considering the totality of the circumstances, we agree with the district court that there is not a substantial controversy of sufficient immediacy and reality to confer declaratory judgment jurisdiction. Stellar sent notice letters to Ferro and Pyrotek in Mexico, and it sued Ferro and Pyrotek in Mexico. Stellar did not even respond to Allied's letter about the Mexican Patent on behalf of Ferro and Pyrotek. Nor has Stellar taken any action in the United States or any action on the '974 patent. Allied has failed to establish a case or controversy regarding Stellar's U.S. patent in the United States under Article III.