The Leahy-Smith America Invents Act contains provisions allowing a “person” other than a patent owner to use three types of administrative review to challenge the validity of a patent after it has been issued, with appeal rights to the Federal Circuit. In Return Mail, Inc. v. United States Postal Service, Return Mail obtained a patent for processing undeliverable mail that it claimed the Postal Service violated. The Postal Service challenged the patent’s validity through the review methods available under the Act. Return Mail prevailed under one form of administrative review, but lost on another. Return Mail argued that the Postal Service was not a “person” eligible to seek review, but the Federal Circuit disagreed. The Court, in a 6-3 opinion by Justice Sotomayor, reversed, holding that the federal government was not a “person,” and thus the Postal Service could not seek review. The Court first noted that when the term “person” is not defined in a statute, existing precedent presumes that the term excludes the federal government—a presumption further suggested by the Dictionary Act. The majority further rejected the argument that although the Act permitted the government to apply for, obtain, and maintain its own patents, that such authority impliedly allowed the government to challenge patents issued to others. Justice Breyer, joined by Justices Ginsburg and Kagan, dissented, arguing that since the Act permitted a “person” to obtain a patent, and the government was entitled to receive patents, then the government must be a person entitled to challenge the patents of others under the Act. A link to the opinion is here.