On a quiet Sunday afternoon in the presidential race, a Secret Service agent opened fire on a man who poked a rifle through a fence as Donald Trump golfed. Just two months earlier, a different gunman tried to kill Trump at a campaign rally. The shooting left one dead and two wounded.

Bomb threats have forced evacuations and lockdowns in Springfield, Ohio, schools, city hall and hospitals after Trump and other politicians amplified a false claim and racist trope that Haitian immigrants there are eating pets.

And both presidential candidates have had to speak from behind bulletproof glass at outdoor events. Federal authorities are already ramping up security for when Congress gathers to certify the winner in January.

The 2024 election season has been repeatedly marked by extraordinary acts and threats of violence, escalating tensions in an already-heated political environment, prompting heightened security measures at events and becoming a more contentious issue in the race with seven weeks of campaigning left to go.

Trump is blaming his Democratic opponents, declaring this week, as Sunday’s incident was still under investigation, that “their rhetoric is causing me to be shot at.” Officials have yet to describe a motive, and there is no evidence that Vice President Kamala Harris or President Joe Biden specifically inspired the attack. At the same time as he has faulted the words of Democrats, Trump has often used incendiary language of his own to describe his rivals, labeling them “the enemy from within.”

Democrats are reminding voters that Trump inspired the mob that stormed the U.S. Capitol on Jan. 6, 2021, and has pledged to pardon rioters if returned to office, a core part of what his critics and historians cite in making the case that he poses a threat to democracy. They have also voiced alarm that his falsehoods will endanger the residents of Springfield. The attention on the city’s Haitian population has led to bomb threats, and community events canceled for security reasons.

Ohio Gov. Mike DeWine (R) said that the dozens of bomb threats were “unfounded” and that many of them came from overseas. But they were disruptive and led to the deployment of state troopers in schools, and Haitian residents have told reporters that they’re staying indoors for fear of reprisal attacks.

While the country’s history includesexamples of violence upending campaigning and governance, from the upheaval of 1968 to the attempted assassinations of Presidents Gerald Ford and Ronald Reagan, this year’s race stands out from others in recent memory, experts said, with some long-simmering fears of violent acts breakinginto the open.

“The United States has an undercurrent of political violence, and periodically for different reasons it bubbles to the top and explodes into riots, insurrections, succession, assassinations and assassination attempts,” said Barbara Perry, a professor at the University of Virginia who directs the presidential oral-history program. This year, she said, “I think this undercurrent has now become the current. Right now it’s at the surface, and it’s rushing along. We’re in a white-water rapids.”

‘A new plateau’

As threats and major episodes of violence have become a recurring element of the political process, many across the country are beginning to accept the incidents as a grim new reality, some observers said, a striking shift from prior elections. Erik Nisbet, a Northwestern University professor who studies political violence, said he’ll be watching political rhetoric in the coming weeks, with concern that the nation is hitting “a new plateau” in public tolerance for threats and bloodshed.

“Does it become the new normal? Do we shrug it off? Are we careful about language or, no, we just don’t care?” Nisbet said. “Are we accepting of this type of violence in our politics?”

The assassination attempt at Trump’s July 13 rally in Butler, Pa., and what the authorities are investigating as a potential attempt at his golf club in Florida on Sunday have spurred plenty of bipartisan condemnations of violence, including from Harris and Biden. Investigators said they were not able to determine the first gunman’s motive and did not find evidence he was driven by political ideology.

But Trump and his allies claimed Democrats bore blame and ramped up the message this week as some evidence emerged that the second alleged gunman, apparently a onetime Trump supporter who later turned away from him, had criticized the former president. Trump’s campaign has repeatedly accused Democrats of endangering him by labeling him a threat to democracy. But the Republican nominee has used the same attack line he has criticized, insisting his opponents are the real threat to democracy, claiming without evidence that they are behind his prosecutions.

A social media account linked to the suspect posted on an array of topics, including the war in Ukraine, and wrote scathingly of Trump this year, saying, “DEMOCRACY is on the ballot and we cannot lose.” Trump’s campaign Monday released a list of quotes from Harris and other Democrats calling Trump a threat to democracy and a video compilation of sound bites they said had stoked hate of Trump, going back to a moment when the comedian Kathy Griffin held up a mock severed Trump head.

“I really believe that the rhetoric from the Democrats,” Trump said in an interview with Washington Post opinion columnist Marc Thiessen on Monday, “is making the bullets fly. And it’s very dangerous.”

Harris’s campaign declined to comment on Trump blaming her for violence. “As we gather the facts, I will be clear: I condemn political violence,” she said in a statement Sunday.

Democrats say there is no equivalence between their rhetoric and Trump’s, pointing to inaccurate and inflammatory claims he and his allies have made, including about Springfield. Trump and his running mate, Sen. JD Vance (R-Ohio), have repeated false rumors about Haitian immigrants in the town, with Trump declaring from a debate stage in prime time last week that people are “eating the dogs” and “eating the cats” — something local police officials had rebutted.

Rep. Brian Schatz (D-Hawaii) criticized Trump for not immediately denouncing the bomb threats in Springfield when a reporter asked about them. Trump said he didn’t know about them. “If anyone asks me if I denounce a bomb threat it’s a yes,” Schatz wrote on social media.

Trump also drew criticism last year for mockingly alluding to an attack on former House Speaker Nancy Pelosi’s husband. A man broke into their home and beat Paul Pelosi with a hammer, fracturing his skull. “She’s against building a wall at our border, even though she has a wall around her house — which obviously didn’t do a very good job,” Trump said of the California Democrat.

On Monday, Trump reiterated his belief that Biden and Harris are “destroying the country, both from the inside and out,” and his descriptions of political opponents as “vermin” and existential threats “from within” the country have particularly alarmed historians and political observers.

“Only one candidate in this race has survived two assassination attempts, and it’s not Kamala Harris,” said Trump campaign spokeswoman Karoline Leavitt when asked about Trump’s heated criticism of Democrats even as he urges them to change their tone.

A prominent Trump ally faced criticism for making violent references rather than tamping down the rhetoric this week. Tech CEO and vocal Trump backer Elon Musk wrote a social media post Sunday after the incident at Trump’s golf course, writing, “no one is even trying to assassinate Biden/Kamala.” Musk later deleted the message.

Trump’s campaign did not comment on the post. Harris’s campaign denounced it.

The New Hampshire Libertarian Party deleted a widely criticized message it posted on social media Sunday saying that “Anyone who murders Kamala Harris would be an American hero.” The Secret Service is investigating the post as a threat against Harris, agency spokesman Nathan Herring said Monday.

It’s not just critics of Harris who have walked back comments. The wife of Lt. Col. Alexander Vindman — a key witness in Trump’s first impeachment — deleted and apologized for a social media post making light of the July assassination attempt that bloodied Trump’s ear. “No ears were harmed. Carry on with your Sunday afternoon,” Rachel Vindman, a Trump critic, wrote after Sunday’s golf club scare, in comments that Trump’s team amplified.

“It was flippant & political violence is a serious issue,” she wrote on Monday. “Whether it’s aimed at a former president, the media, immigrants, or political ‘enemies’ & every incident should be addressed appropriately if we want to change the tenor of our political discourse.”

The threats of violence are also evident in the staging of the campaign trail stops. Trump has increased security at his events since the July shooting: He scaled back appearances at outdoor venues that are harder to secure, and the Secret Service last month approved a plan to surround him at outdoor rallies with ballistic glass normally reserved for select appearances by presidents and vice presidents. Vance has also used the glass recently, and Harris spoke behind a similar shield at her outdoor New Hampshire event this month.

‘A turn for the worse’

U.S. presidents have faced assassination plots over the years, but the attempt on Trump’s life this summer was the closest call in a long time. A man threw a hand grenade toward George W. Bush during a foreign trip in 2005, but Bush was positioned behind a bulletproof barrier and unscathed. Further back, Reagan was seriously wounded by a man trying to kill him in 1981, and Ford survived two assassination attempts in a span of a few weeks in 1975.

Historians also point back to 1968 — when leading Democratic presidential candidate Robert F. Kennedy was assassinated after the murder of the Rev. Martin Luther King Jr., and when Democrats’ convention in Chicago devolved into violent clashes between protesters and police.

Brian Levin, a professor emeritus at California State University at San Bernardino who has studied extremism for decades, said that “targeted violence” — aimed at specific targets such as government officials, public facilities or marginalized groups — “has taken a turn for the worse over the last several years.” He and other researchers pointed to environments that encourage vitriol, a “buffet” of new paths to radicalization on the internet and growing numbers of guns, among other factors.

“Oftentimes what we’re seeing is the most aggressive and emotionally resonant types of messages are the ones that become viral, whether they’re true or not,” Levin said.

People who monitor political violence or threats warn that attacks strain an already fragile security climate ahead of the election. After the shooting at Trump’s July rally, an Institute for Strategic Dialogue report noted: “Although calls for civil war often follow high-profile incidents involving the former president, they were elevated to one of their highest levels in the wake of the attack on Trump. Discussions were frequently accompanied by allegations that the assassination attempt was part of a ‘Deep State’ plot to instigate a civil war between Republicans and Democrats.”

Meanwhile, the Sunday incident reinforced for many Trump supporters the idea that their candidate and their movement is in the crosshairs. On right-wing online forums, there were renewed expressions of outrage and fury along with a smattering of overt calls for violence.

In memes and AI-generated images, some portrayed Trump as a defiant, muscled warrior with a “2-0” record against his would-be assassins.

Maria Sacchetti contributed to this report.