• Jeff Mordock can be reached at jmordock@washingtontimes.com.

• Oct. 5, 2022, 5:00 a.m. ET

Soon after the F.B.I. searched Donald J. Trump’s home in Florida for classified documents, online researchers zeroed in on a worrying trend.

Posts on Twitter that mentioned “civil war” had soared nearly 3,000 percent in just a few hours as Mr. Trump’s supporters blasted the action as a provocation. Similar spikes followed, including on Facebook, Reddit, Telegram, Parler, Gab and Truth Social, Mr. Trump’s social media platform. Mentions of the phrase more than doubled on radio programs and podcasts, as measured by Critical Mention, a media-tracking firm.

Posts mentioning “civil war” jumped again a few weeks later, after President Biden branded Mr. Trump and “MAGA Republicans” a threat to “the very foundations of our republic” in a speech on democracy in Philadelphia.

Now experts are bracing for renewed discussions of civil war, as the Nov. 8 midterm elections approach and political talk grows more urgent and heated.

More than a century and a half after the actual Civil War, the deadliest war in U.S. history, “civil war” references have become increasingly commonplace on the right. While in many cases the term is used only loosely — shorthand for the nation’s intensifying partisan divisions — observers note that the phrase, for some, is far more than a metaphor.

Polling, social media studies and a rise in threats suggest that a growing number of Americans are anticipating, or even welcoming, the possibility of sustained political violence, researchers studying extremism say. What was once the subject of serious discussion only on the political periphery has migrated closer to the mainstream.

But while that trend is clear, there is far less agreement among experts about what it means.

Some elements of the far right view it literally: a call for an organized battle for control of the government. Others envision something akin to a drawn-out insurgency, punctuated with eruptions of political violence, such as the attack on the F.B.I.’s Cincinnati field office in August. A third group describes the country as entering a “cold” civil war, manifested by intractable polarization and mistrust, rather than a “hot” war with conflict.

“The question is what does ‘civil war’ look like and what does it mean,” said Elizabeth Neumann, assistant secretary for counterterrorism at the Homeland Security Department under Mr. Trump. “I did not anticipate, nor did anyone else as far as I know, how rapidly the violence would escalate.”

Ms. Neumann now works for Moonshot, a private security company that tracks extremism online. Moonshot found a 51 percent increase in “civil war” references on the most active pages on 4Chan, the fringe online message board, in the week after Mr. Biden’s Sept. 1 speech.

But talk of political violence is not relegated to anonymous online forums.

At a Trump rally in Michigan on Saturday night, Representative Marjorie Taylor Greene, a Republican from Georgia, said that “Democrats want Republicans dead,” adding that “Joe Biden has declared every freedom-loving American an enemy of the state.” At a recent fund-raiser, Michael T. Flynn, who briefly served as Mr. Trump’s national security adviser, said that governors had the power to declare war and that “we’re probably going to see that.”

On Monday, federal prosecutors showed a jury in Washington an encrypted message that Stewart Rhodes, founder of the Oath Keepers armed extremist group, had sent his lieutenants two days after the 2020 presidential election: “We aren’t getting through this without a civil war.”

Experts say the steady patter of bellicose talk has helped normalize the expectation of political violence.

In late August, a poll of 1,500 adults by YouGov and The Economist found that 54 percent of respondents who identified as “strong Republicans” believed a civil war was at least somewhat likely in the next decade. Only about a third of all respondents felt such an event was unlikely. A similar survey conducted by the same groups two years ago found nearly three in five people feeling that a “civil war-like fracture in the U.S.” was either somewhat or very unlikely.

“What you’re seeing is a narrative that was limited to the fringe going into the mainstream,” said Robert Pape, a political science professor at the University of Chicago and founder of the Chicago Project on Security and Threats.

The institute’s researchers tracked tweets mentioning civil war before and after Mr. Trump announced the search on Mar-a-Lago. In the five preceding days, they logged an average of roughly 500 tweets an hour. That jumped to 6,000 in the first hour after Mr. Trump published a post on Truth Social on the afternoon of Aug. 8, saying “these are dark times for our Nation.” The pace peaked at 15,000 tweets an hour later that evening. A week later, it was still six times higher than the baseline, and the phrase was once again trending on Twitter at month’s end.

Extremist groups have been agitating for some sort of government overthrow for years and, Mr. Pape said, the most radical views — often driven by white supremacy or religious fundamentalism — remain marginal, advanced by no more than 50,000 people nationwide.

But a far larger group, he said, are the people who have been influenced by Mr. Trump’s complaints about the “Washington swamp” and “deep state” forces working against him and his allies.

Those notions, stirred in a smoldering crucible with QAnon conspiracy theories, anti-vaccine views and election denialism, have fueled a growing hostility toward the federal government and rising talk about states’ rights.

“Did you know that a governor can declare war?” Mr. Flynn said at the fund-raiser on Sept. 18, for Mark Finchem, a Republican running for secretary of state in Arizona. “And we’re going to probably, we are probably going to see that.”

Neither Mr. Flynn nor Mr. Finchem responded to a request for comment about the inaccurate remarks. The U.S. Constitution grants Congress the sole power to declare war and, in fact, specifically bars states from engaging in war “unless actually invaded.”

However far-fetched, such ideas are often amplified by a proliferating set of social media channels such as the right-wing platform Gab and Mr. Trump’s Truth Social.

Social media platforms are rife with groups and boards dedicated to discussions of civil war. One, on Gab, describes itself as a place for “action reports,” “combat vids” and reports of killed in action in “the civil war that is also looking to be a 2nd American Revolution.”

In August, a single tweet stating “I think civil war has just been declared” managed to reach over 17 million profiles despite coming from an account with under 14,000 followers, according to Cybara, an Israeli firm that monitors misinformation.

“Ideas go into echo chambers and it’s the only voice that’s heard; there are no voices of dissent,” said Kurt Braddock, an American University professor who studies how terrorist groups radicalize and recruit.

Mr. Braddock said he did not believe these posts indicated any planning for a war. But he worries about what academics call “stochastic terrorism” — seemingly random acts of violence that are, in fact, provoked by “coded language, dog whistles and other subtext” in statements by public figures.

Mr. Trump is adept at making such statements, said Mr. Braddock, citing Mr. Trump’s April 2020 tweet reading “Liberate Michigan!” Less than two weeks later, mobs of heavily armed protesters occupied the state capitol in East Lansing. He also pointed to Mr. Trump’s speech before the Capitol riot on Jan. 6, 2021, when he encouraged thousands of supporters to march to the U.S. Capitol and, later in the same remarks told them, “if you don’t fight like hell, you’re not going to have a country anymore.”

“The statements Trump makes are not overt calls to action, but when you have a huge and devoted following, the chances that one or more people are activated by that are high,” Mr. Braddock said.

A spokesman for Mr. Trump did not respond to requests for comment.

Mr. Trump used the term “civil war” in 2019, when he declared in a tweet that “it will cause a Civil War-like fracture in this Nation from which our Country will never heal” if he was removed from office. Last month, Mr. Trump said there would be “problems in this country the likes of which perhaps we’ve never seen before” if he was indicted over his handling of the classified documents that were the target of the F.B.I. search.

Other Republicans have used language suggesting the country is on the brink. Ms. Greene wrote in August that the Mar-a-Lago search reflected the “type of things that happen in countries during civil war,” in posts to her nearly 900,000 combined followers on Facebook and Telegram. Senator Rick Scott of Florida likened the F.B.I. to the Gestapo, the secret police in Nazi Germany, saying “this cannot be our country.”

Late last month, Senator Ted Cruz, a Republican, told The Texas Tribune he believed immigration legislation was unlikely in part because of a “political civil war.” He has made similar comments before, including a November 2021 call for Texas to secede if Democrats “destroy the country.”

Nick Dyer, a spokesman for Ms. Greene, said that she was “vehemently opposed to political violence” and that her civil war comments were about Democrats, who “are acting like a regime launching a war on their opposition.”

McKinley Lewis, communications director for Mr. Scott, said he had “ZERO tolerance for violence of any kind” but added that he “continues to demand answers” related to the F.B.I.’s Mar-a-Lago search.

Republicans have often argued that their language is political rhetoric and blamed Democrats for twisting it to stoke divisions. It’s Democrats and the left, they said, who are courting violence by labeling Mr. Trump’s supporters adherents of what Mr. Biden has called “semi-fascism.”

In response to a query about Mr. Cruz’s comments, Maria Jeffrey Reynolds, a spokeswoman for the senator, said Mr. Cruz placed blame on President Biden, claiming that he has “driven a wedge down the middle of our country.”

After President Biden delivered his speech on democracy, Brian Gibby, a freelance data entry specialist in Charlotte, N.C., wrote in a Substack post that he believed “the Second Civil War began” with the president’s remarks.

“I have never seen a more divisive, hate-filled speech from an American president,” Mr. Gibby wrote.

Asked by The New York Times to explain his views, Mr. Gibby said he believed Mr. Biden was “escalating a hot conflict in America.” He worries something will happen around the November elections that will be “akin to Jan. 6, but much more violent,” where armed protest groups from both sides of the political spectrum come to blows.

“Plan ahead, stock up, stay safe, get out of cities if you can,” he wrote.