CHICAGO — A would-be assassin is plunging the already tense American political climate into full-blown hysteria as the chaos from bullets flying at former President Donald Trump’s political rally in a Pennsylvania field spread throughout the 2024 electoral landscape.

The historic moment of shocking political violence has put the country on edge heading into the Republican National Convention, which begins Monday in Milwaukee and has morphed from a routine political ritual into a landmark event for a deeply divided nation.

Bloodied from a bullet he said pierced his ear, Trump was rushed off the stage by Secret Service agents Saturday in Butler, Pa. “It is incredible that such an act can take place in our country,” Trump posted on social media soon after the incident.

Now, a political system that already was strained to the breaking point must grapple with the fallout from a rifle shot that came perilously close to killing the GOP presidential candidate. President Joe Biden, Trump’s Democratic opponent, condemned the violent act.

“We cannot allow for this to be happening, we cannot be like this,” said Biden, who for the last two-plus weeks has faced mounting calls to exit the 2024 race due to his age and who spoke with Trump after the shooting.

Trump called for national unity in a social media post early Sunday morning. “In this moment, it is more important than ever that we stand United, and show our True Character as Americans, remaining Strong and Determined, and not allowing Evil to Win,” he wrote.

That message was echoed by political leaders in both parties as prayers and message of support for Trump provided a rare bipartisan rallying cry.

Yet the horror of what happened to Trump also provoked deep anger and outrage, as shock quickly turned to blame, which began to fly before the shooter and any potential motive had been identified. The FBI identified early Sunday that 20-year-old Pennsylvania resident Thomas Matthew Crooks is the individual who fired at Trump.

Crooks killed one rallygoer and injured two others before being killed by the Secret Service.

Already seen as a persecuted figure by many in his party, Trump again was cast as a man whose critics will stop at nothing to keep him from public office.

Such sentiments seem certain to feature prominently at the convention this week as aggrieved supporters vent their frustrations among thousands of Trump’s faithful followers.

“First they tried to silence him. Then they tried to imprison him. Now they try to kill him,” Florida U.S. Rep. Cory Mills wrote on X.

A top Trump campaign aide and a leading candidate to be his running mate both said rhetoric from Biden and Democrats contributed to the climate that led to the shooting.

“Leftist activists, Democrat donors and now even (Biden) have made disgusting remarks and descriptions of shooting Donald Trump,” Trump senior adviser Chris LaCivita said on X. “It’s high time they be held accountable for it, the best way is through the ballot box.”

LaCivita seemed to be referring to comments Biden made to donors recently saying “it’s time to put Trump in a bullseye.”

Ohio U.S. Sen. J.D. Vance, who is speaking at the convention and on Trump’s short list of potential VP candidates, said Biden’s campaign has portrayed Trump as “an authoritarian fascist who must be stopped at all costs.”

“That rhetoric led directly to President Trump’s attempted assassination,” Vance added.

Other Republicans seized on those comments to criticize Biden.

U.S. Rep. Mike Collins shared Biden’s “bullseye” remarks on X and said “Joe Biden sent the orders.”

Democrats have long accused Trump of stoking political violence, from suggesting his supporters should treat rally protesters roughly to inciting the deadly mob that stormed the U.S. Capitol on Jan. 6, 2021 to try and stop the certification of Biden’s victory.

Now the message is being thrown back at Trump’s opponents in the heat of an already explosive campaign that has seen a remarkable whiplash of events, from Trump’s 34 felony convictions to Biden’s disastrous debate performance and now the most high-profile political assassination attempt since a gunman shot President Ronald Reagan in 1981.

The fraught moment is rife with fears of more violence.

“This is not a normal election year and this incident will only escalate the tension in America,” said Jennifer Mercieca, a Texas A&M University professor of communications and journalism and author of a book on Trump’s rhetoric. “The fear is that this act of violence will trigger more suspicion between Americans and more acts of violence.”

Amid the heated rhetoric, some across the political spectrum are urging calm.

U.S. House Speaker Mike Johnson said on the Today Show Sunday that “we’ve got to turn the temperature down in this country.”

“We need leaders of all parties, on both sides, to call that out and make sure that happens so that we can go forward and maintain our free society that we all are blessed to have,” Johnson said.