Since Trump supporters stormed the U.S. Capitol building on Wednesday, evidence has piled up showing that many had violent intentions. Photos of nooses and zip-tie handcuffs and videos of assailants trying to smash their way through barricaded doors have highlighted how much danger members of Congress were in before they were evacuated to safety.

The events of January 6 may be the defining moment of Donald Trump’s presidency. But the siege was also the culmination of years of warnings about the the growing threat posed by far-right extremists. An October report from the Department of Homeland Security, for example, said that “white supremacist extremists” will “remain the most persistent and lethal threat in the Homeland.”

“Can we just accept that the post-9/11 era is over?” Michigan Democrat Elissa Slotkin, a former Defense Department official who touted her experience as a CIA analyst in Iraq and her expertise on terrorism and insurgencies when she ran for Congress in 2018, told MSNBC. “We are in a new era.” While noting that external threats like Russia and China remained, Slotkin continued that “the single greatest national security threat right now is our internal division. It’s the threat of domestic terrorism. It’s that polarization that threatens our democracy.”

However Trump leaves office, a new Congress appears poised to revive a years-old debate on whether the U.S. should expand the legal framework for going after “domestic terrorism.” A group of former Justice Department officials, along with the FBI Agents Association, has long argued that current law makes it easier to prosecute ideologically motivated acts of violence as terrorism if they appear to be inspired by a foreign terror organization like the Islamic State, and that a domestic terror statute would allow them to prosecute white supremacist terror — like Dylann Roof’s mass shooting in a Black church in Charleston, South Carolina — on equal footing.

But civil liberties advocates are wary of such a move, noting that federal law enforcement already has powerful tools to investigate and prosecute acts of domestic terrorism without any new laws, and that importing the anti-terrorism framework risks creating broad and vague powers that could be used to go after activists or religious minorities.

“Anyone familiar with the scope of surveillance and targeting of Black political dissent, or Muslim communities, knows that law enforcement has all the tools it needs to aggressively disrupt and hold accountable those who planned and participated in the storming of the Capitol,” said Diala Shamas, a staff attorney with the Center for Constitutional Rights. “Why they didn’t raises serious questions, but it was not because their hands were tied. We don’t need new terrorism designations.”

It’s also unclear exactly what a new domestic terrorism law might look like or whether President-elect Joe Biden would support it.

In November, the Wall Street Journal reported that an informal group of advisers had suggested that Biden step up efforts to counter extremism, including by creating a White House post and an interagency task force to oversee efforts to counter domestic extremism. On his campaign website, Biden promised to “work for a domestic terrorism law that respects free speech and civil liberties, while making the same commitment to root out domestic terrorism as we have to stopping international terrorism.” A transition spokesperson told The Intercept that Biden has not yet taken a position on whether “domestic terrorism” should be a federal crime or what a statute should look like and declined to comment further.

In an address last week while announcing his nomination of Merrick Garland for attorney general, Biden called members of the mob that stormed the Capitol “insurrectionists” and “domestic terrorists,” and said that Trump had incited an “all-out assault on our institutions of democracy.”

In U.S. terrorism prosecutions, the defendant isn’t charged with “domestic terrorism” or “international terrorism” directly. In fact, U.S. law didn’t have a definition of “domestic terrorism” until October 2001. Most terrorism prosecutions rely on broadly construed charges of “material support” for international terror groups, even if the defendants have few direct ties to those networks.

Sayfullo Saipov, for example, an Uzbek immigrant who drove a truck down a bike lane in downtown Manhattan, killing eight people, was charged with providing “material support” to ISIS after claiming its cause as his own, despite having no other ties to the group.

But the “material support” provisions work differently for domestic terror acts, because the U.S. government doesn’t designate domestic organizations, even those like the neo-Nazi Atomwaffen Division, as terrorist groups. Instead, terrorism law can be used to charge someone for providing material support for certain offenses, more than 50 of which can be domestic. They include killing a federal officer, using weapons of mass destruction, and setting off explosives, but not many mass shootings.

Although terrorism laws can apply to right-wing violence, a 2019 review by The Intercept found that as a matter of practice, they rarely are. The review found that since the 9/11 attacks, 268 right-wing extremists have been prosecuted in federal court, but Justice Department prosecutors only used anti-terrorism statutes in 38 of those cases. That formed a sharp double standard with international terrorism prosecutions, in which such laws were used more than 400 times.

Jason Blazakis, a former State Department Official and professor at the Middlebury Institute of International Studies who has written in support of a domestic terrorism statute, told The Intercept that existing law is a difficult and arbitrary patchwork that makes it hard to prosecute certain acts, like politically motivated mass shootings, under terrorism laws.

“When someone like [Tree of Life synagogue shooter] Robert Bowers kills 18 people in a Pittsburgh synagogue, and he’s not considered a domestic terrorist because he used a handgun and not a weapon of mass destruction. It really points to the absurdity of the law as it exists today,” Blazakis told The Intercept. “If that were an individual inspired by ISIS, they’d be charged with an act of terrorism.”

Blazakis said he supports a narrowly tailored domestic terror statute that would make it easier to charge individual, politically motivated acts of violence, rather than trying to designate domestic groups as “terrorist,” which would raise First Amendment issues.

But critics say the expansion of federal law enforcement power since 9/11 makes additional terrorism laws unnecessary and potentially dangerous. “The FBI has, since 9/11, gained extraordinary authorities to investigate. In order to open an assessment — the lowest level of investigation — the only thing that the FBI needs to have is an ‘authorized purpose,’” said Faiza Patel, co-director of the Brennan Center’s Liberty and National Security Program. “Given the fact that there are at least 50 statutes that count as domestic terrorism, I feel confident that they could find an authorized purpose. They have certainly done that when they have gone after Muslims and other minority communities.”

The “terrorist” label is also “vulnerable to political exploitation,” Patel noted, pointing to Republicans’ use of terrorism language to describe antifa last summer.

During the nationwide protests that followed George Floyd’s death last year, Trump and Republican legislatures showed an awareness of the political effects of the terrorism label. Shortly after Trump tweeted that he wanted to designate antifa a “terrorist organization,” former Attorney General Bill Barr issued a statement: “The violence instigated and carried out by Antifa and other similar groups in connection with the rioting is domestic terrorism and will be treated accordingly.” A number of Republican members of Congress also introduced resolutions urging the designation, which were condemned by civil liberties groups.

There have already been attempts in Congress to introduce a domestic terror statute, but they haven’t made it out of committee. In 2019, Rep. Adam Schiff, D-Calif., introduced legislation that would allow certain crimes to be prosecuted as domestic terrorism if they were aimed at intimidating civilians, influencing government policy by intimidation or coercion, or violently disrupt government business. But civil liberties groups, including the American Civil Liberties Union, opposed the bill in part because they said it would give broad discretion to the attorney general to decide when to prosecute offenses as terrorism. (Blazakis said the Schiff bill had built in checks that could prevent abuse, including a requirement that prosecutions be reviewed by the independent Privacy and Civil Liberties Oversight Board.)

“If that statute had been enacted last summer,” Patel said, “Attorney General Barr would have had the discretion to treat property damage from the anti-racism protests as terrorism. And I don’t think we want to leave that kind of discretion to the attorney general, even when you trust the attorney general.” A spokesperson for Schiff did not respond to a request for comment.

Lawmakers should think carefully about applying any broad new legal frameworks for terrorism given how far-reaching post-9/11 measures turned out to be, Jameel Jaffer, executive director of the Knight First Amendment Institute, told The Intercept by email.

“Many of the intelligence and law enforcement authorities that were created or expanded after 9/11 were expanded with al Qaeda in mind — that is, with the idea that these new authorities were necessary to address the threat presented by a relatively small number of committed terrorists based overseas,” Jaffer wrote. “But those expanded authorities ended up having dramatic implications for the lives and liberties of millions of people both inside and outside the United States, the vast majority of whom had absolutely nothing to do with al Qaeda. Before we go down this road again, we should think very carefully about whether new authorities are actually needed, how those authorities are likely to be used, and how they might be abused. It’s important to remember that all of the authority we invest in this administration will be available to every future administration has well.”