When Rep. Steve Scalise, a Louisiana Republican, was shot by an angry gunman at an Alexandria baseball field in June, shaken politicians on Capitol Hill said the perpetrator, James Hodgkinson, had an invisible accomplice – the nation’s hyperbolic, polarized political discourse.

Suggesting that liberal demonization of conservatives inspired Hodgkinson’s bloody quest, both House Speaker Paul Ryan, a Republican, and Minority Leader Nancy Pelosi, the House’s top Democrat, vowed to keep the gloves on during the next partisan fight. A poll released June 26 seems to validate that pledge: A majority of Americans on the right and left believe the rhetoric in the nation’s capitol has worsened since the 2016 presidential election.

But President Donald Trump stomped on Washington’s moment of zen.

Less than 24 hours after Capitol Police killed Hodgkinson in a shootout, and as Scalise lay hospitalized in critical condition, Trump scratched his itchy Twitter fingers with a bitter message about Hillary Clinton and the ongoing investigation of Russian meddling in the 2016 election, the latest in a string of attacks on his political adversaries.

Weeks later, both Republicans and Democrats said Trump crossed a line when, responding to her on-air criticism of him, Trump tweeted that TV host Mika Brzezinski had shown up at one of his swank Mar-a-Lago parties, bleeding from a botched facelift.

Yet even as the Marist/NPR poll on public attitudes, released June 26, revealed that seven out of 10 Americans say the level of civility in Washington has gotten worse since Trump came to Washington, the president capped off a weekend of slapping around the Washington news media with one last Monday morning swipe on Twitter.

“At some point” he wrote, “the Fake News will be forced to discuss our great jobs numbers, strong economy, success with ISIS, the border & so much else!”

The disconnect between voters turned off by vilification, legislators who worry it could prompt violence and a president who’s made it his calling card, has lawmakers wrestling with a paradox: Whether it’s possible to lower the temperature of the political debate when the president himself keeps turning up the heat, 140 characters at a time.

“I don’t think our president has helped the situation any,” says Roy Gutterman, an associate professor at Syracuse University and director of The Tully Center for Free Speech. “To the degree that he’s provided a role model for the public, it has been a pretty horrendous one. I think the man is [harming the presidency] every time he engages in that sort of public discourse.”

Trump will attack his opponents, Gutterman says, “at the drop of a hat.”

Indeed, Trump entered politics by claiming former President Barack Obama was born in Kenya, won office despite declaring his Democratic opponent was a criminal, continuously argues that news he doesn’t like has been fabricated and uses Twitter like Don Rickles used a microphone.

But the White House says Trump suffers “vicious attacks” from his foes every day, so he has a right to fight fire with fire, even if the rhetoric he uses is inflammatory.

“I think the American people elected somebody who’s tough, who’s smart and who’s a fighter, and that’s Donald Trump,” deputy press secretary Sarah Huckabee Sanders told reporters in late June.

George Lakoff, a linguist at the University of California-Berkeley, suggests that Trump’s personal attacks might turn off most people, but they energize a large swath of his core supporters who are tired of politically-correct, spare-all-feelings speech.

“Donald Trump expresses out loud everything they feel — with force, aggression, anger, and no shame,” Lakoff wrote in an essay, “Understanding Trump.”

“All they have to do is support and vote for Trump and they don’t even have to express their ‘politically incorrect’ views, since he does it for them and his victories make those views respectable,” Lakoff wrote. “He is their champion. He gives them a sense of self-respect, authority, and the possibility of power.”

Yet while the focus on political rhetoric comes in the aftermath of the shooting of Scalise – a brazen daytime act that rocked the country – most political scientists say we’ve been here before. The blurring of lines between free speech, passionate political debate and outright vilification of one’s opponents, they say, stretches back to the nation’s founding.

Writing about Patrick Henry, his fellow revolutionary and political rival, Thomas Jefferson argued that “what we have to do, I think, is devoutly to pray for his death.” Abigail Adams, wife of President John Adams, didn’t hold back in her assessment of Alexander Hamilton: “I have read his heart and his wicked eyes many a time. The very devil is in them.”

In 1856, speech led to violence when Rep. Preston Brooks, a pro-slavery South Carolinian, clubbed Rep. Charles Sumner, a Massachusetts abolitionist, with a cane on the House floor, foreboding the Civil War. Sen. Barry Goldwater, GOP presidential contender who hated liberal anti-Vietnam War protests, famously told Republicans in 1964 that “extremism in the defense of liberty is no vice,” a speech many say was a literal call to arms.

“I think it has always been the case that in American political discourse there have always been people who have said things that are hurtful and uncivil and bordering on inciting violence,” says Gutterman.

What’s different with Trump, Gutterman says, is that he regularly ignores unspoken but widely accepted rules of thumb: It’s politics, not personal, and presidents must meet a higher standard.

Throughout the 2016 presidential primary campaign, Trump mocked his GOP rivals (“Little Marco,” “1-for-38 Kasich” “Low-energy Jeb” ). He dissed Clinton – a former first lady, senator and secretary of state – as “Crooked Hillary,” egging on his supporters’ chants of “Lock her up!” As president, he’s taunted Senate Minority Leader Charles Schumer as “Cryin’ Chuck,” blasted former FBI Director James Comey as a liar and a leaker, said the investigation into Russian influence of the 2016 election is “a witch hunt” and takes regular potshots at the “lying media.” That includes tweets about “the failing New York Times” and re-tweeting a doctored pro wrestling video of himself body-slamming a person labeled “CNN.”

At the same time, however, a core percentage of the nation’s voters either looked past the insults or saw them as virtues. Trump won just 45 percent of the popular vote, a near-historic low, but enough to take the Electoral College and win the White House decisively.

“If there is [a line], it’s not a legal one – it’s a moral and ethical one,” Gutterman says. “I think there is a line, and I think the history of the office of the presidency, prior to the ascension of President Trump, is the benchmark to use. The fact that the president is so far outside the norm [compared with his predecessors] is a sign that he’s crossed it.”

Voters who are upset about the tone of political arguments in Washington, Gutterman says, should look in the mirror first.

“The fact that Donald Trump got elected,” Gutterman adds, “says a great deal about the temperament and character of the electorate.”

In their minds, Lakoff says, Trump’s supporters typically feel validated by his rejection of “‘P.C. culture’ – public pressure against their [bigoted] views and against what they see as ‘free speech,'” Lakoff wrote in his essay.

Obama’s two terms “created outrage” among many white lower- and middle-class conservatives, who latched onto Trump’s “birther” movement to delegitimize Obama’s presidency, and the real estate mogul’s simple “Make America Great Again” message resonated, Lakoff wrote. Trump’s base “refused to see him as a legitimate American” particularly since “his liberal views contradicted almost everything else they believe as conservatives,” he wrote.

There are signs, however, that the president’s overheated rhetoric may be doing long-term damage to the democracy. .

According to the NPR/Marist poll, 70 percent of the public believes political discourse has gotten worse under Trump – a marked increase since July 2009, when a Gallup poll showed only 35 percent of the respondents believed the debate over the country’s direction had deteriorated.

The dim view stretched across party lines: 81 percent of Democrats and 61 percent of Republicans believe political dialogue has suffered since the president took office. At the same time, trust in public institutions – Congress, the media, the courts – is down significantly across the board, according to the poll.

What’s missing is “a check and balance system … If you say something crazy, or say something that’s knowingly false, there will be people to correct it,” particularly journalists, Gutterman says. But, he adds, “we’re also seeing a complete disregard of that vetting, and it’s coming from the top down,” most notably Trump’s tweets rejecting widely-accepted facts and brushing off legitimate journalism from reputable sources as “fake news.”

At some point, Gutterman says, voters alone have the power to stop the name-calling and personal attacks by making different choices at the ballot box. But he’s not optimistic it will happen anytime soon.

“It’s hard to predict where we’re gonna go,” Gutterman says. Change must come, he says; “otherwise we’ll just implode. The only other alternative would be an outright revolution. And God help us if that happens.”