Almost anybody can ask the Patent Trial and Appeal Board (PTAB) to review the validity of a patent under the America Invents Act (AIA). Companies that have been sued for patent infringement are the most frequent petitioners, but trade associations, nonprofits, defensive patent aggregators and even hedge funds shorting patent owners’ stock are welcome at the PTAB.

But now the Supreme Court looks poised to exclude one type of AIA petitioner: the U.S. government. On Oct. 26, the justices agreed to hear Return Mail v. United States Postal Service. The justices limited argument to a single question: “Whether the government is a ‘person’ who may petition to institute review proceedings under the AIA.”