It is only by a miracle that former president Donald Trump is alive today. A shift of a couple millimeters and the assassin’s bullet that merely wounded his upper ear could have killed him or left him permanently disabled. Had that happened, the streets of America might already be filling with enraged mobs clamoring for retribution. For months, extremists and agitators at both ends of the nation’s political spectrum have been warning of a coming civil war. In its most recent “Homeland Threat Assessment,” the Department of Homeland Security predicted that “the 2024 election cycle will be a key event for possible violence.” It isn’t only Trump who has dodged a potentially deadly fate. It’s all of us.

There is a long and awful history of political violence in this country, even at the highest levels. Sixty years ago President John F. Kennedy was murdered in Dallas by Lee Harvey Oswald. In the decades since, Americans have witnessed the murder of one prominent presidential candidate — Robert F. Kennedy in 1968 — and the near-murder of another — George C. Wallace in 1972. Just two months after Ronald Reagan took the oath of office in 1981, a deranged John Hinckley Jr. shot him outside a Washington, D.C., hotel.

At this writing, there are serious unanswered questions about the atrocity on Saturday night near Pittsburgh. How could a gunman have gained access to a rooftop within firing range of a candidate under Secret Service protection? What motivated the shooter, who was identified on Sunday as 20-year-old Thomas Matthew Crooks? Public records showed that the would-be assassin, who was instantly killed by Secret Service snipers, was both a registered Republican and a donor to the Progressive Turnout Project. Why did law enforcement officials fail to act when eyewitnesses reportedly called attention to someone with a rifle “bear crawling” on a nearby building?

But the most urgent question looming over this terrible incident is whether it will jolt a polarized nation into cooling the apocalyptic rhetoric that has turned American political life into a seething caldron of anger, hatred, and intolerance?

Trump’s near-assassination was quickly condemned by political leaders from both parties, including President Biden — whose reelection campaign immediately suspended all political communication, including attack ads against Trump — as well as former presidents Bill Clinton, George W. Bush, and Barack Obama, plus the Republican and Democratic leaders in the Senate. Former House speaker Nancy Pelosi, whose husband was savagely beaten by an attacker in 2022, released a message saying: “I thank God that former President Trump is safe.”

But none of us will be safe for much longer if Americans cannot relearn how to disagree without despising each other. More than at any time since World War II, the fabric of society seems to be coming apart at the seams. For those with clashing party loyalties, finding common ground has grown all but impossible. Divergent opinions are treated as deadly threats, to be resisted not with courtesy and a willingness to hear each other out but with hostility and slander.

Our election campaigns are now dominated by what political scientists call “negative partisanship” — voters are motivated more by hatred of the opposing party than by loyalty to their own. Again and again that hatred has expressed itself in violent language, or even outright mayhem.

Many Republicans were quick to blame Saturday’s shooting on fearmongering from Democrats about the desperate stakes in the election. “The central premise of the Biden campaign is that President Donald Trump is an authoritarian fascist who must be stopped at all costs,” tweeted Senator J.D. Vance of Ohio, a Republican. “That rhetoric led directly to President Trump’s attempted assassination.”

It is quite true that liberal politicians, celebrities, and activists have for years been inciting their followers with over-the-top rhetoric about confronting Trump and his loyalists. “When they go low, we kick them. That’s what this new Democratic Party is about,” former attorney general Eric Holder declared in 2018. Biden has anathematized Trump’s “MAGA crowd” as “the most extreme political organization that’s existed in American history.” Another Trump presidency, Biden told his followers last week, would be “deadly serious — deadly serious” and so it was “time to put Trump in a bullseye.”

But from Trump has come language just as menacing, even gleeful in its celebration of violence. For years he has whipped up his followers by calling to punch hecklers in the face and warned of “riots” if he doesn’t get his way. The destructive mayhem he whipped up on Jan. 6, 2021, was among the most scandalous outrages ever committed by a US president, and equally appalling is the way he continues to celebrate the US Capitol rioters as martyrs and “hostages.”

Anyone not blinded by partisanship knows that unhinged incitement to hatred and violence is coming from the left and the right alike. Neither Team Red nor Team Blue has clean hands. Trump didn’t start the fire, but he accelerated it. Biden, who vowed that his top priority as president would be to lower the flames, accelerated them still further.

Now, for the first time in 43 years, a man elected president of the United States has been shot in public by a would-be assassin. Our political leaders have one last chance to pull back from the brink. Pray they have the wisdom to seize it.