When the New Jersey Office of Homeland Security and Preparedness issued its terrorism threat assessment for 2020 last week, it noted a marked shift.

The threat level from violent, homegrown extremists, and specifically white supremacists, was marked in red as the top category: “High.” The threat from the Islamic State, Al Qaeda and their ilk was demoted to third, in green: “Low.”

Terrorism experts believe that holds true for the entire United States.

“In the U.S., more people are killed by far-right extremists than by those who are adherents to Islamist extremism,” said Mary McCord, a Georgetown University law professor and a former senior Justice Department official for national security. Her comments came at a discussion last week at the 9/11 Memorial and Museum, which commemorates victims of the most notorious attack by international terrorists on American soil.

Even as the menace from homegrown extremists grows more explicit, however, law enforcement is wrestling with how to combat it. That challenge has spawned a fervent debate over whether the United States needs a new law to specifically criminalize domestic terrorism, or whether such a statute would threaten basic First Amendment rights.