American history is repeating itself in a most macabre way.

If everything unfolds as expected, Donald Trump will deliver a triumphant speech in Milwaukee next Thursday night to accept the Republican presidential nomination.

Adrenaline will be coursing through that crowd for another reason: His admirers will celebrate his very survival from an apparent campaign-stop assassination attempt.

Literally one block away from the convention site, an uncannily similar event occurred. Another former president, also seeking a comeback, who’d just been struck by a bullet in an attack at a campaign stop celebrated his miraculous survival with adoring supporters.

“I don’t know whether you fully understand that I have just been shot,” Teddy Roosevelt told them, in 1912, a few metres from where Trump is scheduled to accept the nomination.

“But it takes more than that to kill a bull moose.”

Roosevelt showed the crowd his blood-stained speaking notes, which may have saved his life by slowing the bullet that slightly punctured his chest.

There’s something else Roosevelt did that day, and we’ll find out quickly whether Trump emulates him now during a fragile moment for American democracy.

He turned the temperature down.

Surrounded by a potential mob, Roosevelt urged everyone to stay peaceful. His supporters wanted action against the gunman, chanting “Kill him!” Roosevelt encouraged first them, then the arresting police officers, to leave the man unharmed. The shooter, John Schrank, was later remanded to a state institution.

It’s what happened north of the border, too, when the leader of the Parti Québécois was targeted by a shooter in 2012. In the aftermath, Pauline Marois maintained rhetoric to avoid stoking more violence.

Trump weighed his words carefully in his first statement on Saturday’s shocking events. He thanked police, said he’d been shot in the ear, extended his condolences to a victim in the crowd and said nothing is known about the now-deceased shooter.

The fear now gripping political violence-watchers

“It is incredible that such an act can take place in our country,” Trump said.

In fact, if only it were incredible. 

People who study political violence have been unnerved for a while. Now, this is a scene from the nightmare scenarios that have been playing in their heads.

• Cross Country Checkup is asking: What’s your reaction to the latest U.S. news? Fill out this form and you could appear on the show or have your comment read on air.

We’ve already seen congressman Steve Scalise, a Republican, survive a shooting. Gabrielle Giffords, a Democrat, survived a shooting. An intruder bludgeoned Nancy Pelosi’s husband with a hammer in her home.

Nearly one-quarter of U.S. presidents have survived assassination attempts or been killed.

And scholars of threats to democracy have been especially unnerved about the current political climate in the hyper-polarized, hyper-angry United States.

After the Jan. 6, 2021, attack on the U.S. Capitol, one leading expert in the field, Robert Pape, began conducting regular surveys of thousands of respondents to track the darker corners of the American public mood.

The University of Chicago scholar told CBC News about his latest survey. Conducted last month, it adds sobering context to Saturday’s disturbing event.

He said the survey from June 20 to 24 suggests 10 per cent of American adults agree that use of force is justified to prevent Trump from returning to office.

That’s 26 million people. And one-third of them, Pape said, own guns. On the flip side, he said about seven per cent of American adults, or 18 million people, half of whom own guns, support using force to restore Trump to office.

“The shooting of former president Trump is a consequence of such significant support for political violence in our country,” said Pape, director of the Chicago Project on Security and Threats, adding that retaliatory threats against President Joe Biden are also a concern.

“Political leaders from both parties and at all levels of government — the president, Senate and House leadership, governors and mayors — must immediately condemn political violence from whichever side of politics it arises.”

2 types of political response 

Events like Saturday’s can fling a country down different paths, said Michael Miller, a scholar on democratization and democratic decline at George Washington University.

He said there are close parallels in recent history: The stabbing of Jair Bolsonaro in Brazil in 2018, and the shooting of Imran Khan in Pakistan in 2022 — both of whom survived. 

“I wouldn’t say either incident changed the country’s politics dramatically,” Miller said.

Bolsonaro went on to win the presidency, then lost it, and his supporters stormed several of Brazil’s political institutions last year.

Then there are more disturbing examples, where acts of violence beget more violence, political instability, democratic crackdowns or worse, like in the aftermath of political assassinations in the U.S. in 1968, coup attempts in Venezuela and Turkey or political violence entrenching 20th-century dictatorships in Europe.

“Sudden violent events can have major negative effects,” Miller said. 

“They create a licence in many actors’ minds that they can resort to violence in response because they’re no longer playing a purely constitutional game. 

“But it matters a lot how elites respond. They can push to take down the temperature or use it to inflame polarization for their own ends. I’m not optimistic about the direction Trump takes it.”

Numerous U.S. politicians called for calm. They represent untold millions of thoughtful, temperate people in the country. 

Some sought answers: Republicans have, for instance, requested that the head of the Secret Service appear for a hearing to discuss what some witnesses at the Pennsylvania shooting scene described as a catastrophic failure.

A witness told the BBC that Trump supporters saw the rifle-toting shooter on the nearby rooftop and tried, and failed, to get Secret Service officers to intervene before the shooting started and they killed the gunman.

Others did what they always do: Water the roots of political hatred in this country, hoping to harvest a few more morsels of attention for themselves.

WATCH | Witnesses describe moment shooter fired at Trump, and the chaos after:

Witnesses describe moment shooter fired at Trump, and the chaos after

Witnesses say the shots fired at former U.S. president Donald Trump appeared to come from outside the area secured by the Secret Service. The FBI said it had taken the lead in investigating the attack.

They include anti-Trump accounts on social media wishing he’d been killed, or claiming he staged the attack for political reasons.

They also include, notably, pro-Trump members of the U.S. Congress.

Like one Republican from Georgia, Mike Collins, who suggested Biden should be criminally charged, claiming that the president incited this a few days ago for saying it was time for his own party to stop its infighting and “put Trump in a bull’s-eye.”

Another Georgia Republican blamed Democrats and the media.

“May God have mercy on our enemies because we will NOT,” Marjorie Taylor Greene posted on X, formerly Twitter, on Saturday.

At this point, the whole nation could use such mercy.

This isn’t a Republican problem, or a Democratic problem, but an American problem, said one Republican convention-goer in Milwaukee.

“It’s a sad day in American politics,” said James Mathews, who owns a small business in Alabama.

“Whether it’s Democrat or Republican, that just shouldn’t happen.”