But Justice Antonin Scalia said the question before the court did not involve the First Amendment.Later, Justice Kennedy said: "You have a First Amendment argument... I understand that. But let’s just concentrate on the property ownership.” And Scalia said: “You keep sliding into the First Amendment issue... We’re only interested in whether the statute applies."
“You can raise it,” he said, “but we don’t have to listen to it.”..
The Court is reviewing a 9th Circuit opinion that said that the federal statute under which Apel was convicted didn't apply to the situation in which the feds had given some public access to the military base (which they'd done to give access for protests).
ADDED: The wording of the first sentence of the linked report (at the NYT) made me think Apel was not actual on the base but only near it: "John D. Apel... was convicted of breaking federal law by entering an area set aside for protests near the main entrance to Vandenberg Air Force Base." Near the main entrance — you'll see if you keep reading — was on the grounds of the base, but it was "an area open to the public on the other side of a painted green line that separates the closed part of the base from the Pacific Coast Highway."