The Supreme Court jousted for an hour Wednesday about whether the First Amendment allows the government to prosecute people for lying about earning military honors, and, if so, what else might be fair game.

Lying about whether your child received a medal? wondered Justice Samuel A. Alito Jr.

Holocaust deniers? asked Justice Ruth Bader Ginsburg.

People who lie about extramarital affairs? offered Justice Elena Kagan.

Justice Sonia Sotomayor tried out a personal example: “I take offense when someone I’m dating makes a claim that’s not true.”

The Supreme Court jousted for an hour Wednesday about whether the First Amendment allows the government to prosecute people for lying about earning military honors, and, if so, what else might be fair game. (Pablo Martinez Monsivais/AP)

At the end of the arguments in U.S. v. Alvarez , it was unclear how many of what Solicitor General Donald V. Verrilli Jr. called the court’s “slippery slope” questions were in the form of genuine concern or simply playing devil’s advocate.

The questions raise difficult issues, Verrilli conceded, but should not keep the court from upholding the Stolen Valor Act, which makes lying about receiving some of the nation’s highest military awards and decorations a crime, punishable in some cases by incarceration.

The statute is “about as narrow as you can get,” Verrilli said, and targets with “pinpoint accuracy” only “calculated factual falsehoods.” And the government since the days of George Washington has shown an interest in promoting valor and bravery in its military and keeping “charlatans” from usurping that glory.

It seemed from the general tenor of the arguments that the justices were looking for ways to agree with Verrilli that the exception to the First Amendment’s speech protections was narrow.

He seemed to have one sure supporter in Justice Antonin Scalia, whose comments were uniformly protective of the government’s interests.

“When Congress passed this legislation, I assume it did so because it thought that the value of the awards that these courageous members of the armed forces were receiving was being demeaned and diminished” by those who falsely claimed them, Scalia said.

And Verrilli had one clear skeptic in Sotomayor.

“I thought the core of the First Amendment was to protect even against offensive speech,” she said. “You can’t really believe that a war veteran thinks less of the medal that he or she receives because someone’s claiming that they got one.”

But the rest of the court seemed more conflicted. Chief Justice John G. Roberts Jr., for instance, asked Verrilli if the government could criminalize lying about whether one received a high school diploma.

“Where do you stop?” he asked Verrilli.

On the other hand, he pounced when the lawyer representing Xavier Alvarez, a California water district board member who was prosecuted for lying about receiving the Congressional Medal of Honor, took his turn at the podium.

“What is the First Amendment value in a lie, (a) pure lie?” Roberts asked Jonathan D. Libby, a federal defender from California.

Similarly, Justice Anthony M. Kennedy worried about the government prosecuting liars. “It presumes that the government is going to have a ministry of truth . . . and I just don’t think that’s our tradition,” Kennedy said.

On the other hand, Kennedy said, “it does seem to me that you can argue that this is something like a — a trademark, a medal in which the government and the armed forces have a particular interest, and we could carve out a narrow exception for that.”

The questions reflect what lower courts have found to be a tension in some of the court’s First Amendment precedents.

Certain categories of speech fall outside of First Amendment protection: obscenity, defamation, fraud, incitement and speech integral to criminal conduct.

The court has held for years that “truth” may not be the standard for deciding whether speech is protected by the First Amendment. It also has said that “there is no constitutional value in false statements of facts.”

Any government attempt to punish falsehoods must steer clear of inhibiting constitutionally protected public debate.

Kagan told Libby to assume she agreed with the court’s previous ruling that “there is no constitutional value in a false statement of fact, and the reason why we protect some false statements of fact is to protect truthful speech.”

If so, she asked “how is it that this statute will chill any truthful speech?”

Libby said he conceded that it may not.

“That’s a big concession, Mr. Libby,” Kagan replied.

The Roberts court has been reluctant to expand the types of speech that lack First Amendment protection.

In several recent high-profile First Amendment cases, the court struck down a broadly written law on depicting animal cruelty, upheld the rights of a controversial group that demonstrates at military funerals and blocked a California law that attempted to outlaw the sale of violent video games to minors.

The Reporters Committee for Freedom of the Press and 23 news organizations, including The Washington Post, filed a brief supporting Alvarez to argue that upholding the law would reverse “the basic presumption against official oversight of expression.”

Veterans groups, on the other hand, said falsely claiming the honors was theft. There was some interest among the justices in trying to decide whether falsely claiming the honors led to a type of gain that amounted to fraud.

If the law is struck down, supporters in Congress already are preparing a version that would make it a crime to benefit from lying about being an award-winner.