At a conservative rally in western Idaho last month, a young man stepped up to a microphone to ask when he could start killing Democrats.

“When do we get to use the guns?” he said as the audience applauded. “How many elections are they going to steal before we kill these people?” The local state representative, a Republican, later called it a “fair” question.

In Ohio, the leading candidate in the Republican primary for Senate blasted out a video urging Republicans to resist the “tyranny” of a federal government that pushed them to wear masks and take F.D.A.-authorized vaccines.

“When the Gestapo show up at your front door,” the candidate, Josh Mandel, a grandson of Holocaust survivors, said in the video in September, “you know what to do.”

And in Congress, violent threats against lawmakers are on track to double this year. Republicans who break party ranks and defy former President Donald J. Trump have come to expect insults, invective and death threats — often stoked by their own colleagues and conservative activists, who have denounced them as traitors.

From congressional offices to community meeting rooms, threats of violence are becoming commonplace among a significant segment of the Republican Party. Ten months after rioters attacked the United States Capitol on Jan. 6, and after four years of a president who often spoke in violent terms about his adversaries, right-wing Republicans are talking more openly and frequently about the use of force as justifiable in opposition to those who dislodged him from power.

In Washington, where decorum and civility are still given lip service, violent or threatening language still remains uncommon, if not unheard-of, among lawmakers who spend a great deal of time in the same building. But among the most fervent conservatives, who play an outsize role in primary contests and provide the party with its activist energy, the belief that the country is at a crossroads that could require armed confrontation is no longer limited to the fringe.

Political violence has been part of the American story since the founding of the country, often entwined with racial politics and erupting in periods of great change. And elements of the left have contributed to the confrontational tenor of the country’s current politics, though Democratic leaders routinely condemn violence and violent imagery. But historians and those who study democracy say what has changed has been the embrace of violent speech by a sizable portion of one party, including some of its loudest voices inside government and most influential voices outside.

In effect, they warn, the Republican Party is mainstreaming menace as a political tool.

Omar Wasow, a political scientist at Pomona College who studies protests and race, drew a contrast between the current climate and earlier periods of turbulence and strife, like the 1960s or the run-up to the Civil War.

“What’s different about almost all those other events is that now, there’s a partisan divide around the legitimacy of our political system,” he said. “The elite endorsement of political violence from factions of the Republican Party is distinct for me from what we saw in the 1960s. Then, you didn’t have — from a president on down — politicians calling citizens to engage in violent resistance.”

From his earliest campaigning to the final moments of his presidency, Mr. Trump’s political image has incorporated the possibility of violence. He encouraged attendees at his rallies to “knock the hell” out of protesters, praised a lawmaker who body-slammed a reporter, and in a recent interview defended rioters who clamored to “hang Mike Pence.”

Yet even with the former president largely out of the public eye and after a deadly attack on the Capitol where rioters tried to overturn the presidential election, the Republican acceptance of violence has only spread. Polling indicates that 30 percent of Republicans, and 40 percent of people who “most trust” far-right news sources, believe that “true patriots” may have to resort to violence to “save” the country — a statement that gets far less support among Democrats and independents.

Such views, routinely expressed in warlike or revolutionary terms, are often intertwined with white racial resentments and evangelical Christian religious fervor — two potent sources of fuel for the G.O.P. during the Trump era — as the most animated Republican voters increasingly see themselves as participants in a struggle, if not a kind of holy war, to preserve their idea of American culture and their place in society.

Notably few Republican leaders have spoken out against violent language or behavior since Jan. 6, suggesting with their silent acquiescence that doing so would put them at odds with a significant share of their party’s voters. When the Idaho man asked about “killing” political opponents at an event hosted by the conservative activist Charlie Kirk, Mr. Kirk said he must “denounce” the question but went on to discuss at what point political violence could be justified.

In that vacuum, the coarsening of Republican messaging has continued: Representative Paul Gosar, Republican of Arizona, this week tweeted an anime video altered to show him killing Representative Alexandria Ocasio-Cortez and swinging two swords at Mr. Biden.

Lee Drutman, a senior fellow at the left-leaning group New America who has studied political violence, said there was a connection between such actions and the growing view among Americans that politics is a struggle between enemies.

“When you start dehumanizing political opponents, or really anybody, it becomes a lot easier to inflict violence on them,” Dr. Drutman said.

“I have a hard time seeing how we have a peaceful 2024 election after everything that’s happened now,” he added. “I don’t see the rhetoric turning down, I don’t see the conflicts going away. I really do think it’s hard to see how it gets better before it gets worse.”

Democrats are seeking Mr. Gosar’s censure, arguing that “depictions of violence can foment actual violence and jeopardize the safety of elected officials.”

The ranking G.O.P. lawmakers, Senator Mitch McConnell and Representative Kevin McCarthy, did not respond to repeated requests for comment. Mr. McCarthy, who initially condemned the Jan. 6 attack and said “violence is never a legitimate form of protest,” more recently has joked about hitting Nancy Pelosi in the head with a gavel if he were to replace her as speaker. Like nearly all of the members of his caucus, Mr. McCarthy has said nothing about Mr. Gosar’s video.

For his part, Mr. Gosar suggested that critics were overly thin-skinned, insisting that the video was an allegory for a debate over immigration policy. He was slaying “the policy monster of open borders,” not Ms. Ocasio-Cortez or Mr. Biden, his office said. “It is a symbolic cartoon. It is not real life.”

Carlos Curbelo, a Republican former congressman from Florida who is a critic of Mr. Trump, said Republicans needed to take a stronger approach against violent language and intimidation tactics.

“I do think the problem is more acute among Republicans because there are a handful of Republican officials who have no limits,” he said. “Your country and your integrity should be more important to you than your re-election.”

The increasing violence of Republican speech has been accompanied by a willingness of G.O.P. leaders to follow Mr. Trump’s lead and shrug off allegations of domestic violence that once would have been considered disqualifying for political candidates in either party.

Herschel Walker, the former professional football player running for Senate in Georgia, is accused of repeatedly threatening his ex-wife’s life, but won Mr. Trump’s endorsement and appears to be consolidating party support behind his candidacy. Mr. Trump also backed the Ohio congressional campaign of Max Miller, who faces allegations of violence from his ex-girlfriend, the former White House press secretary Stephanie Grisham. Mr. Miller has sued Ms. Grisham for defamation.

And Sean Parnell, a Senate candidate in Pennsylvania who was endorsed by Mr. Trump, appeared in court this week in a custody fight in which his estranged wife accuses him of choking her and physically harming their children. He denies it.

Senator Rick Scott of Florida, the chairman of the National Republican Senatorial Committee, declined to repudiate Mr. Parnell. Asked on CNN whether Mr. Parnell was the right candidate for the job, he said, “We’ll see who comes out of the primary.”

There is little indication that the party has paid a political price for its increasingly violent tone.

Even after corporations and donors vowed to withhold donations to the G.O.P. in the wake of the Jan. 6 attack, Republicans out-raised Democrats this year. And they outperformed expectations in the elections this month, capturing the Virginia governorship, winning a host of upset victories in suburban contests and making a surprisingly strong showing in New Jersey.

Yet violent talk has tipped over into actual violence in ways big and small. School board members and public health officials have faced a wave of threats, prompting hundreds to leave their posts. A recent investigation by Reuters documented nearly 800 intimidating messages to election officials in 12 states.

And threats against members of Congress have jumped by 107 percent compared with the same period in 2020, according to the Capitol Police. Lawmakers have been harassed at airports, targeted at their homes and had family members threatened. Some have spent tens of thousands on personal security.

“You don’t understand how awful it is and how scary it is until you’re in it,” said Representative Debbie Dingell, a Michigan Democrat who praised a Republican colleague, Representative Fred Upton, for publicly sharing some of the threats he received after voting to approve the infrastructure bill. (Mr. Upton’s office did not respond to requests for comment.) “But not telling people that this violence isn’t OK makes people think it is OK.”

Ms. Dingell, who said she was threatened by men with assault weapons outside her home last year after she was denounced by Tucker Carlson on his Fox News show, shared a small sample of what she said were hundreds of profanity-laden threats she has received.

“They ought to try you for treason,” one caller screamed in a lengthy, graphic voice mail message. “I hope your family dies in front of you. I pray to God that if you’ve got any children, they die in your face.”

Bradford Fitch, president of the Congressional Management Foundation, which advises lawmakers on issues like running their offices and communicating with constituents, said he now urged members not to hold open public meetings, an American tradition dating back to the colonies, because of security concerns. Politics, he said, had become “too raw and radioactive.”

“I don’t think it’s a good idea right now,” Mr. Fitch said. “I hope we can get to a point where we can advise members of Congress that it’s safe to have a town-hall meeting.”

But even at right-wing gatherings of the like-minded, there is a shared assumption that political confrontation could escalate into violence.

At a Virginia rally last month for conservative supporters of Glenn Youngkin, the Republican candidate for governor, the urgency of a call to arms was conveyed right from the opening prayer. The speaker warned of the looming threat of “communist atheists.”

“Heavenly Father, we come before you tonight,” said Joshua Pratt, a conservative activist. “Your children are in a battle, and we need your help.”