When a lone gunman stormed into a church in Sutherland Springs, Texas, on Nov. 5 and murdered 26 people attending Sunday services, it was called a mass shooting.
Similarly, after a sniper killed 58 people in Las Vegas on Oct. 1, the deadliest mass shooting in modern U.S. history, a morbidly familiar debate arose over whether or not to call it"domestic terrorism."
"It was an act of pure evil," President Trump remarked. But he joined law enforcement officials in refraining from calling it a terrorist action.
Trump and other officials took a strikingly different tone after an attack in New York on Oct. 31, when a truck driven by a legal U.S. resident, originally from Uzbekistan, raced down a bike lane, killing eight people. The incident was quickly labeled an act of terror by the president and New York officials, and is being investigated as such.
Just hours after the incident, Trump tweeted: “I have just ordered homeland security to step up our already extreme vetting program. Being politically correct is fine, but not for this!” He also called for an end to the diversity immigrant visa lottery, the program through which the perpetrator received his green card.
All three incidents caused horrific death and destruction and were perpetrated by men who, it can be safely presumed, were severely troubled.
So why the difference in terminology?
From a legal standpoint, explains NPR's national security correspondent Greg Myre, much of the distinction comes down to motive.
The Patriot Act, enacted in the wake of the 9/11 terrorist attacks, defines domestic terrorism -- like international 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."
But unlike international terrorism, there's no actual federal charge of "domestic terrorism." According to the Justice Department, the government can't file domestic terrorism charges against someone because no such law actually exists.
Alleged perpetrators, Myre notes, can be charged with federal terrorism only when they are suspected of acting on behalf of one of almost 60 groups labeled by the State Department as a foreign terrorist organization. Some of these have virtually become household names, groups like the Islamic State and al-Qaida. Others are far more obscure. Almost all are Islamic.
And that's the primary reason why authorities were so quick to call the New York incident a terrorist attack. Sayfullo Saipov, who is Muslim, reportedly yelled “Allahu Akbar,” Arabic for “God is great," during the attack. He also claimed he was inspired by ISIS videos and requested to have an ISIS flag in his hospital room.
That embrace of ISIS, regardless of how strong the connection really was, served from a legal standpoint as enough of a motive for federal authorities to charge Saipov with committing an act of terror.
Meanwhile, because the motives of the shooters in the two other incidents remain ambiguous, and neither appear to have had any affiliations with foreign "terrorist" groups, the suggestion of terrorism was quickly dismissed.
"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," writes Myre.
He points to James Alex Fields, a suspected white supremacist who is accused of driving his car into a crowd in Charlottesville, Virginia, in August, killing a female demonstrator. He faces state murder charges but not terrorism charges.
It's also why Dylann Roof, who murdered nine African-American worshipers at a Charleston, South Carolina, church in 2015 with the stated goal of starting a race war, was sentenced to death for a range of federal and state crimes, but was not charged with terrorism.
Even Timothy McVeigh, who killed 168 people in the 1995 bombing of a federal building in Oklahoma City, an attack he said was motivated by his hatred for the government, and which is widely considered the nation's deadliest act of domestic terrorism, was ultimately tried and executed for the murder of federal officers, but not for terrorism.
A growing number of voices are calling for acts of domestic extremism, especially those stemming from white supremacist ideologies, to be charged as terrorism. But there's little indication that this will legally change anytime soon.
The roots of a loaded charge
The term terrorism has its roots in the "Reign of Terror" during the French Revolution, in which the newly empowered government publicly executed thousands of suspected dissenters and opponents in an effort to stem resistance. The term referred to the government committing violent acts against its own people as a means of political control.
In his famous 1794 address, the French leader Maximilien Robespierre argued that government-sponsored terror was a necessary tactic in strengthening and sustaining democracy.
"Terror is nothing more than speedy, severe and inflexible justice; it is thus an emanation of virtue; it is less a principle in itself, than a consequence of the general principle of democracy, applied to the most pressing needs of the patrie (homeland)."
Terrorism and Islam
In more recent times, though, the meaning of terrorism flipped, referring instead to violent actions committed against the state.
And since the al-Qaida attacks of Sept. 11, 2001, many Americans think of terrorism as synonymous with Islamist extremism, even though the definition is much broader. The association has contributed to a notable rise in Islamophobia in the U.S. and other nations that have experienced recent attacks.
A 2017 Georgia State University study examined why some terrorist attacks receive so much more media attention than others, and concluded that social identity is the largest predictor of news coverage.
"Muslim perpetrators received, on average, 449% more coverage than other attacks,” the study found.
In an interview with NPR’s Shankar Vedantam, a researcher from the study, Erin Kearns, said that “when the perpetrator was Muslim, people were much more likely to consider it to be terrorism than when the perpetrator was not Muslim. In those cases, people are more likely to say that perhaps it's a hate crime or not be sure how to classify it.”