Sunday’s shooting deaths in Garland, Texas, of two gunmen with suspected Islamic extremist ties who reportedly attacked an exhibit of cartoons depicting the Muslim prophet Muhammad is reminiscent of January’s massacre of 12 people at the Charlie Hebdo satirical magazine in Paris, and has ignited fresh fears of domestic terror.

The Texas incident, in which police said an officer killed the heavily armed pair after they attempted to storm the exhibit and managed to open fire and hit a security guard in the ankle, also has provoked renewed debate over what constitutes free speech as opposed to hate crime.

The event did not just feature an exhibit of cartoons; it was an incendiary contest soliciting caricatures of the Islamic leader, organized by a woman branded the leader of a hate group with a history of making anti-Muslim comments. The event also featured a speech by a right-wing Dutch politician who is on an al Qaeda hit list.

As an institution granted First Amendment privileges, this newspaper supports free speech, which the U.S. Supreme Court has interpreted differently over the years.

Back in 1919 the justices upheld the conviction of a man named Charles Schenck who had been found guilty of violating the Espionage Act of 1917 because he printed 15,000 fliers urging young men to resist military conscription. The court ruled that although Mr. Schenck’s actions weren’t as flagrant as “falsely shouting fire in a theater,” they did present a “clear and present danger” to the nation’s security.

But 50 years later, the court reversed itself on “clear and present danger” in supporting the free-speech right of Ku Klux Klan leader Charles Brandenburg to use inflammatory language and racial slurs at a televised Ohio rally, ruling that his rant wasn’t intended “to incite imminent lawless action.”

We do not have enough information now to judge whether Pamela Geller, organizer of Sunday’s “Jihad Watch Muhammad Art Exhibit and Cartoon Contest” had any such specific intentions, but you don’t have to be Oliver Wendell Holmes to realize that her actions would inflame Islamic militants. Mrs. Gellar once told The New York Times she believed the only “moderate Muslim is a secular Muslim” and that when Muslims “pray five times a day … they’re cursing Christians and Jews five times a day.”

Mrs. Gellar also has called President Obama the “love child” of Malcolm X, claiming he was once involved with a “crack whore.”

Even though the jury may still be out on whether her actions were intended to incite “imminent lawless action,” details about the two men gunned down outside the exhibit certainly point in that direction.

Law-enforcement authorities report that one suspect, identified as Elton Simpson, linked himself to ISIS in a tweet posted just before the attack. Officials say he had been convicted of making a false statement involving international and domestic terrorism. The other suspect, identified as Nadir Soofi, was Simpson’s roommate in a Phoenix apartment.

Regardless of whether the contest was constitutionally protected free speech or illegal incitation to lawlessness, it certainly was maliciously ill advised.

We support the rights of those to speak on behalf of the causes they represent, but like the Supreme Court condemn those who stage loathsome publicity stunts for the sole purpose of fomenting violence.