OAKWOOD VILLAGE, Ohio — As a group of prominent black pastors listened, the top federal prosecutor in northern Ohio, Justin E. Herdman, spoke recently at Mount Zion church about the prospect that a gunman could target one of their congregations.
The subtext was clear. Mr. Herdman is among a group of federal law enforcement officials who have begun speaking more forthrightly about fighting domestic terrorism from the front lines. They want to reassure a skeptical public that the Justice Department is forcefully combating racist and politically motivated violence in the Trump era, amid their own mounting concerns about a possible surge in attacks sparked by the 2020 election.
“When I sit in church,” Mr. Herdman told the pastors, “I have one eye on what’s going on at the altar, and I have got one eye on the entrance to the sanctuary.”
“Mm-hmm,” the pastors responded in unison.
The community relations effort is the most visible of several aggressive steps by federal prosecutors and F.B.I. agents to combat domestic terrorism. The bureau has about 850 open investigations across the United States. Prosecutors have backed rewriting the laws on domestic terrorism. And in northern Ohio, Mr. Herdman has encouraged his investigators to use wiretaps, one of their most intrusive tools, in such cases.
Their efforts show how federal law enforcement officials are fighting domestic terrorism and its underlying ideologies, including white nationalism and neo-Nazism, as they navigate not only demands to do more to stop high-profile mass shootings but also limits on their power, like First Amendment protections for hate speech.
At the church in Oakwood Village, a middle-class suburb southeast of Cleveland, Mr. Herdman was joined by the area’s top F.B.I. agent, Eric B. Smith, who expressed concern that the bitter divisions that have colored the nation’s political discourse will only worsen in an election year and could stoke more violence.
“One of the great concerns for us in the upcoming year is this domestic terrorism threat,” Mr. Smith said. “People are simply conducting acts of terror because it’s their side.”
Mr. Herdman, a career prosecutor and former intelligence officer in the United States Navy Reserve, gained attention recently for his performance at a news conference announcing charges against a white nationalist suspected of threatening the Jewish Community Center of Youngstown, about 60 miles from Cleveland.
Investigators discovered an AR-15 military-style assault rifle, World War II-era Nazi propaganda and a Hitler Youth knife in the basement of the suspect, 20-year-old James P. Reardon of New Middletown.
Evoking recent mass shootings, Mr. Herdman denounced Mr. Reardon and his toxic views, describing Nazism and racial superiority as failed ideologies.
“Threatening to kill Jewish people, gunning down innocent Latinos on a weekend shopping trip, planning and plotting to perpetrate murders in the name of a nonsense racial theory, sitting to pray with God-fearing people who you execute moments later — those actions don’t make you soldiers, they make you criminals,” Mr. Herdman said.
His words resonated. Letters, phone calls and emails poured in. “Thank you for so accurately describing the limits of fanaticism,” wrote Larry Schwarz, who is Jewish and lives in Hatboro, Pa. “I have never heard the case made so eloquently and so cogently.”
Mr. Herdman explained in an interview why he was compelled to speak out. “I wanted to lay down the marker,” he said. “I couldn’t let it go unsaid what the position of our office is.”
Mr. Reardon’s case is one of dozens that Mr. Herdman’s office has pursued in recent months. The F.B.I.’s Cleveland field office, which has a dedicated domestic terrorism squad, plans to add more investigators soon.
Mr. Herdman has encouraged his investigators to work aggressively, including using wiretaps to thwart domestic terrorists. Investigators must clear a high bar to start a wiretap; it requires the approval of a federal judge, and prosecutors must show that less invasive methods have failed or likely would.
Mr. Herdman’s office has charged others with making threats against federal law enforcement officers and against Representative Alexandria Ocasio-Cortez, Democrat of New York and a frequent target of conservative criticism.
Those arrests came after a man opened fire in August in a nightclub on the other side of the state, in Dayton, gunning down nine people and wounding 19. The gunman possibly embraced troubling beliefs, including anti-government, racist and misogynist views, according to a law enforcement official.
Civil liberty and Muslim advocacy groups have accused the government of being slow to recognize the deadly threat as investigators focused heavily on Islamic terrorists.
“For too long, the F.B.I. was myopically targeting Muslims as potential terrorists,” said Faiza Patel, co-director of the Liberty and National Security Program at the Brennan Center for Justice at the New York University Law School. “It is now feeling pressure from Congress and the public to address white nationalist violence, so we are seeing a wave of investigations and prosecutions.”
Around the country, federal law enforcement officials have vocally taken on domestic terrorism. Thomas T. Cullen, the top prosecutor in the Western District of Virginia and a Trump appointee, has moved aggressively to convict white supremacists who break the law.
He prosecuted James Fields Jr., the avowed white supremacist from Ohio who steered his Dodge Challenger into a crowd of protesters near a white nationalist rally in Charlottesville, Va., in 2017, killing a young woman and injuring dozens. As Mr. Fields was sentenced in June to life in prison, Mr. Cullen said his attack was “motivated by this deep-seated racial animus.”
Mr. Cullen has targeted local members of a Southern California-based violent white supremacist group, the Rise Above Movement. Two regions of growing concern are the West Coast and the states around the Great Lakes, where the F.B.I. has seen more arrests than in other parts of the country.
Other prosecutors in Virginia as well as in Florida and Los Angeles have also targeted white supremacists.
Agents have also ramped up activity against members of Atomwaffen, one of the most violent extremist groups in the country, arresting suspected members on gun charges and asking a local judge to seize the weapons of one in the Seattle area because he was a risk to the public.
The group, which has dozens of members across the country, wants to start a race war in the United States, according to the F.B.I. The bureau is also concerned about an Atomwaffen offshoot, Feuerkrieg Division.
Federal prosecutors have backed a domestic terrorism bill that they say could aid in investigations, but the effort has stalled at the White House, a Justice Department official said.
Any legislation also would probably face stiff resistance from civil rights activists over its First Amendment implications. An existing federal statute defines domestic terrorism roughly as people trying to use political violence to intimidate others but carries no penalties.
The F.B.I. made 107 domestic terrorism-related arrests in the fiscal year that ended in September, a total roughly consistent with recent years.
“Certainly, the most lethality in terms of terrorist attacks over the recent years here in the homeland has been on the domestic terrorism side,” Christopher A. Wray, the F.B.I. director, told lawmakers last month. Just days after his testimony, the F.B.I. charged a white supremacist in Colorado with plotting to blow up a synagogue.
Though he and other senior law enforcement officials have spoken out about the rise of hate crimes and political violence, including Attorney General William P. Barr, who condemned both in a July speech on combating anti-Semitism, they stand out somewhat in terms of how the politics of fighting domestic terrorism have played out in Washington.
President Trump has stoked race-based fears and praised “both sides” after the deadly Charlottesville attack. He also continues to lend credibility to white nationalists and anti-Muslim bigots by amplifying suspect accounts on Twitter, according to an investigation by The New York Times.
But after years of prodding, the Department of Homeland Security finally affirmed in September that domestic terrorism was a national security threat while earlier this year, the F.B.I. established a domestic terrorism-hate crimes fusion cell.
The Justice Department should also craft and make public a strategy to combat white nationalist violence, Ms. Patel said, adding that the government does not necessarily need new laws to fight domestic terrorism, just new priorities.
In Ohio, Mr. Herdman expects extremism to persist. “Just based on the trend line, I don’t see where it goes down,” he said.
He has prosecuted cases associated with a mixed bag of ideologies, including anarchists, people obsessed with mass killings and sovereign citizens, who view government as illegitimate.
The F.B.I. late last year arrested Damon M. Joseph, a white supremacist-turned-aspiring-jihadist who was planning to attack a synagogue in the Toledo area. The arrest came weeks after the mass shooting at a Pittsburgh synagogue that killed 11 worshipers, an attack that Mr. Joseph had praised.
That same week, agents arrested a Toledo couple, Elizabeth Lecron and Vincent Armstrong, both 23, on charges of planning to blow up a bar there. Investigators said Ms. Lecron consumed Nazi literature and was infatuated with mass killers, posting photographs and comments on social media glorifying the Columbine school shooters, who killed 13 and wounded 21 in Littleton, Colo., in 1999, and the man convicted in the killing of nine black worshipers at a church in Charleston, S.C., in 2015.
In a journal, Mr. Armstrong wrote: “I have a vision. A vision to kill. To hunt the unwilling.”
Ms. Lecron pleaded guilty in August to providing material support to terrorists, a crime frequently charged in international terrorism cases — but not domestic ones. Mr. Armstrong also pleaded guilty to his role in the thwarted attack.
At the church, Mr. Herdman, who has given the same sober talk to Muslim and Jewish religious leaders, offered a reminder about why the Justice Department was founded after the Civil War: to fight the Ku Klux Klan, whose members have historically terrorized black people and targeted churches.
“We’re here for you,” he told the pastors.
Katie Benner contributed reporting from Washington.
