The investigation into the Las Vegas shooting is still in the early stages, yet there already is a familiar debate about whether to call it an act of "domestic terrorism."
"It was an act of pure evil," President Trump said — but the president and law enforcement officials have refrained from calling it terrorism.
Several members of Congress, from both parties, did describe the attack as terrorism, including Jim Cooper, a Democrat from Tennessee.
Two key questions crop up every time this debate takes place.
First, what was the attacker's motive?
The Patriot Act defines domestic terrorism as an attempt to "intimidate or coerce a civilian population; to influence the policy of a government by intimidation or coercion; or to affect the conduct of a government by mass destruction, assassination, or kidnapping."
So far, law enforcement officials say they don't have an answer on the motives of Stephen Paddock, 64.
"We don't know what his belief system was at this time," said Clark County Sheriff Joe Lombardo, referring to the shooter.
The second important point is that there isn't a federal charge of "domestic terrorism." The Patriot Act's definition gives the Justice Department broad authority to investigate an individual or any group a suspect might be affiliated with. But the federal law doesn't come with an actual criminal charge.
To be charged with terrorism, a person has to be suspected of acting on behalf of one of nearly 60 groups that the State Department has declared a foreign terrorist organization. Some are well-known, including the Islamic State and al-Qaida, while others are far more obscure. Most, but not all, are Islamist.
A person who carries out a mass attack and survives can face a range of charges, but unless the person is linked to one of the banned groups, a federal terrorism charge won't be one of them.
Consider the following cases, all of which prompted discussions of domestic terrorism:
-- Suspect James Alex Fields is accused of driving his car into a crowd in Charlottesville, Va., in August, killing a female counterprotester who came out to march against white nationalists. Fields faces state murder charges — but not terrorism.
-- Dylann Roof has been convicted of and sentenced to death for a host of federal and state crimes in the shooting deaths of nine African-Americans at a Charleston, S.C., church in 2015. He said he wanted to start a race war. But terrorism wasn't among the many charges.
-- Timothy McVeigh was widely described as carrying out the worst act of domestic terrorism when he killed 168 people in a 1995 bombing of a federal building in Oklahoma City. By his own admission, his motive was clearly political — he hated the federal government. Yet he was convicted of and put to death for killing federal officers and variety of other charges — but not for terrorism.
The al-Qaida attacks of Sept. 11, 2001, made terrorism virtually synonymous with Islamist extremism in the minds of many. The political debate appears to be shifting, with growing numbers calling for domestic extremism to be identified as terrorism as well. But that's a political discussion, not a legal one.
Legally speaking, many in law enforcement say they are wary of creating a criminal charge of domestic terrorism.
They say they already have the tools to investigate and bring charges in any case involving an attempted or actual mass attack — and creating a domestic terrorism charge could quickly raise all sorts of First Amendment questions, about free speech, religion and ideology.
There's one additional wrinkle to consider: Some states, including Nevada, have their own anti-terrorism laws. But those state laws tend to be invoked rarely.
Greg Myre is a national security correspondent. Follow him @gregmyre1.
ROBERT SIEGEL, HOST:
The investigation into the Las Vegas shooting is in the early stages, and already there's a debate over whether to call this crime an act of domestic terrorism. We're going to take a moment now to look at what is and isn't defined as terrorism. NPR national security correspondent Greg Myre is here. Hiya.
GREG MYRE, BYLINE: Hey, Robert.
SIEGEL: First, who's calling what happened in Las Vegas domestic terrorism, and who isn't?
MYRE: Well, the president - he called it an act of pure evil. Law enforcement in the Las Vegas area - they say they still don't know the motive behind the attack. However, there are some members of Congress, both Republicans and Democrats, including the Democratic National Committee, who have tweeted out and said that this is terror or domestic terrorism.
SIEGEL: And what accounts for the difference?
MYRE: Well, you know, terrorism is not about the level of violence or how many people are killed. It's the motivation. And so far, we don't know what the shooter, Stephen Paddock, had in mind, whether this was personal or political. That's still under investigation. But then there's this very important distinction when we get to federal law because terrorism is defined as acting on the behalf of a foreign terror group.
Now, the State Department has a list of about 60 groups, many of them well-known - the Islamic State, al-Qaida. However, there's no actual criminal charge in the U.S. for domestic terrorism. So if you're acting alone or even on behalf of a U.S. group, it's not really considered terrorism.
SIEGEL: So there's no formal criminal charge for that. But doesn't it instill terror in people just the same?
MYRE: Oh, absolutely. We've been talking about exactly the same act, but it just - it depends whether or not you're acting on behalf of a illegal, foreign terror group. And in fact this is really the third case in the past several months where we've had a white male involved in a case where this debate has come up about domestic terrorism. There was Charlottesville back in August where the white nationalists were rallying and a suspect allegedly - he drove a car and killed a woman. But he's been charged with murder, not terrorism.
In Alexandria, we had the shooting at the congressional Republicans practicing baseball. The attacker was killed there. We could go back and back all the way back to Timothy McVeigh, who killed 168 people with a bomb. It was not - he was not charged with terrorism.
SIEGEL: Is this mere semantics? Or why does it matter what we call it?
MYRE: Well, a lot of prosecutors and law enforcement people say it doesn't really matter. They say they have plenty of tools, whether it's murder charges or hate crimes or something like that, where they can do what they need to do. Now, the Patriot Act does actually define domestic terrorism, and this does give prosecutors expanded powers to carry out investigations. But again, there's no criminal charge that goes with it.
And there are some who say we are overlooking the threat of domestic terror because of the focus on foreign Islamic groups. But there's not really a big push to get a domestic terrorism charge, and a lot of people say this would put the government in the position of defining ideology and religion and defining certain groups that are not considered legitimate.
SIEGEL: And that could run up against problems with the First Amendment.
SIEGEL: That's NPR's Greg Myre. Thanks.
MYRE: Thank you. Transcript provided by NPR, Copyright NPR.