Congress and the FBI are under more pressure than ever to enact and enforce a federal domestic-terrorism statute in the wake of two mass shootings over the weekend in El Paso, Texas, and Dayton, Ohio, that left 31 dead and several injured.

While authorities haven't determined a motive for the Dayton suspect, they found that the El Paso shooter was driven by white nationalism and anti-immigrant rage.

The federal government has had broad authority to investigate and prosecute jihadist violence and other foreign terrorism cases since the September 11 attacks.

But it's been unable to address homegrown extremism as effectively because of civil liberties concerns, and because the US has no domestic terrorism statute.

"It's a double standard," Daryl Johnson, a former senior domestic terrorism analyst at the U.S. Department of Homeland Security, told The Associated Press . "We should be calling all ideologically motivated violence terrorism, whether it comes from the white variety or the Muslim variety."

But others in the law enforcement community say the problem isn't the lack of a specific domestic terrorism statute, but the FBI's refusal to take white nationalist violence seriously.

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Following the mass shooting at a Walmart in El Paso, Texas by last weekend, right-wing extremists have now killed more people on US soil than jihadists since the 9/11/01 terror attacks.

According to the nonpartisan New America think tank, jihadists have killed 104 people inside the US since 9/11, while far-right terrorism has killed 109 peopole.

In 2018, right-wing extremists killed more people in the US than in any year since the Oklahoma City bombing in 1995, according to the Anti-Defamation League.

For years, when Americans hear the word "terrorism," they've likely associated it almost exclusively with jihadism. The federal government was focused on domestic terrorism for much of the 1990s, but after the September 11 attacks, the US national security apparatus pivoted to focus almost exclusively on combating jihadism and other categories of overseas terrorism.

The Patriot Act, passed after 9/11, gave the government broad authority to thwart foreign terrorist plots in this regard.

But the issue of combating far right extremist violence is much thornier given the lack of a specific domestic terrorism law in the federal criminal code, in addition to civil liberties concerns.

A double standard?

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After a white supremacist in 2015 killed nine black people in a historically African-American church in Charleston, South Carolina, activists, media figures, and others criticized the Justice Department for not charging the gunman with domestic terrorism.

Domestic terrorism, as the FBI defines it, is "perpetrated by individuals and/or groups inspired by or associated with primarily US-based movements that espouse extremist ideologies of a political, religious, social, racial, or environmental nature."

Experts said the Charleston church shooter's motive appeared racially or politically motivated. Along these lines, many of the Justice Department's critics contended it was exhibiting a double-standard when it came to violence committed by Muslims versus non-Muslims.

That criticism has increased exponentially in the aftermath of the El Paso and Dayton, Ohio, mass shootings over the weekend, and a growing number of experts are calling on Congress to classify domestic terrorism as a federal crime.

"Domestic terrorism is a threat to the American people and our democracy," the FBI Agents Association said in a statement released Tuesday. "Acts of violence intended to intimidate civilian populations or to influence or affect government policy should be prosecuted as domestic terrorism regardless of the ideology behind them."

It continued: "FBIAA continues to urge Congress to make domestic terrorism a federal crime. This would ensure that FBI Agents and prosecutors have the best tools to fight domestic terrorism."

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Thomas O'Connor, then the president of the FBI Agents Association, wrote an op-ed for The Hill following the deadly white nationalist violence in Charlottesville, Virginia in 2017. In it, O'Connor contended that US law had resulted in "uncertainty for law enforcement officials and the public, as it makes federal officials depend on city codes to prosecute domestic terrorists."

He also suggested Congress pass legislation making it a crime for a person to "commit, attempt, or conspire to commit an act of violence intended to intimidate or coerce a civilian population or to influence government policy or conduct."

' When you dismiss it as a mass shooting or a hate crime or some crazed gunman, you're minimizing what impact it has'

But there's a significant divide between legal and national security experts on how a domestic terrorism law would work in practice.

Proponents of such a measure say that even naming white supremacist violence for what it is could be a significant step toward combating the problem.

"When you dismiss it as a mass shooting or a hate crime or some crazed gunman, you're minimizing what impact it has," Daryl Johnson, a former senior domestic terrorism analyst at the U.S. Department of Homeland Security, told The Associated Press.

"It's a double standard," he added. "We should be calling all ideologically motivated violence terrorism, whether it comes from the white variety or the Muslim variety."

Read more: A former senior FBI official said agents are hamstrung in fighting white nationalist violence because they're 'wary of pissing off the guy in the Oval Office'

Mary McCord, a former national security prosecutor, wrote in Lawfare last year that such a law would provide for better record-keeping and analysis. She added that it would also push back on the widely held view that the federal government didn't care as much about domestic terrorism and white nationalism as it did foreign terrorism, particularly of the kind influenced by radical Islam.

A 'lack of authority' or just an unwillingness to go after white nationalists?

That said, there are significant concerns among civil-liberties advocates that broadening the federal government's powers could test the limits of free speech.

Martin Stolar, a New York civil-rights lawyer, told The New York Times that a sharpened focus on white supremacist violence would also test whether Americans approved of aggressive oversight when the targets were white and not Muslim.

"If they did the same thing that they did with the Muslims, they'd say every white guy is a potential terrorist," Stolar told The Times. "You can't do that with white people. The blowback would be outrageous."

Meanwhile, some in the law enforcement community also say that there's too much emphasis on the lack of a specific domestic terrorism statute, and the real problem is the FBI is refusing take white nationalist violence seriously.

Michael German, a former FBI agent who is now a fellow at the Brennan Center for Justice, wrote in a December 2018 op-ed, "The claim that existing terrorism statutes are insufficient is false ... Congress has given the federal government substantial tools to address far-right violence."

German said that the Justice Department's "inattention to far-right violence" is not due to a "lack of authority," but a product of "longstanding policy and practice."

"Though many hate crimes fit the definition of domestic terrorism under federal law — violence or threats intended to intimidate or coerce a civilian population — and can properly be labeled as such, the FBI, as a matter of policy, regards them as lesser crimes," German added.

"Congress has given DOJ officials plenty of tools to attack far-right violence. They just require the will to use them."