Lying about receiving a military award, like the Medal of Honor, is a pretty despicable thing to do.

But then, so is lying to your spouse about an affair or about earning a college degree that you never completed.

The U.S. Supreme Court was right to rule today that the Stolen Valor Act and its criminalization of lying about receiving military honors is an unconstitutional violation of the First Amendment. Outlaw that and it opens the door to the government outlawing all kinds of lying.

"As Justice Kennedy observes, the government's argument simply lacked a limiting principle," said ACLU Deputy Legal Director Jameel Jaffer. "Perfectly respectable people sometimes lie to protect their privacy, avoid hurt feelings, make others feel better, duck minor obligations, or protect themselves and others from prejudice.

"If the court had endorsed the government's sweeping argument, the government could regulate all of these false statements, and even criminalize them, he continued. "The First Amendment reserves to individual citizens, not the government, the right to separate what is true from what is false, and to decide what ideas to introduce into private conversation and public debate."

As it stands, only a few forms of speech are restricted in the United States, including defamation, incitement and obscenity. That's as it should be.