The extraordinary images of a defiant Donald Trump pumping his fist in the air, with blood on his face, being rushed off the stage by the Secret Service are not just history-making – they may well alter the course of November’s presidential election.
This shocking act of political violence will inevitably have an effect on the campaign. US Secret Service agents shot dead the suspect at the scene. And law enforcement sources told the BBC’s US partner CBS News that they are treating the attack as an assassination attempt.
The picture – of a bleeding Mr Trump, fist in the air, being escorted away- was quickly posted on social media by his son Eric Trump with the caption: “This is the fighter America needs.”
President Joe Biden appeared on TV shortly after the shooting and said there was no place in America for political violence like this. He expressed concern for his Republican opponent and said he hoped to speak with him later tonight.
Mr Biden’s election campaign paused all political statements and is working to take down its television ads as quickly as possible, clearly believing that it would be inappropriate to attack Donald Trump at this time and instead concentrating on condemning what’s happened.
Politicians from across the political spectrum – people who agree on very little else – are coming together to say violence has no place in a democracy.
Former Presidents Barack Obama, George W Bush, Bill Clinton and Jimmy Carter were all quick to denounce the violence and said how relieved they were that Trump was not seriously hurt.
But some of Mr Trump’s closest allies and supporters are already blaming Mr Biden for the violence, with one Republican congressman accusing the president of “inciting an assassination” in a post on X.
Senator JD Vance, who is thought to be on the shortlist to become Trump’s vice-presidential candidate, said the rhetoric from the Biden campaign led directly to this incident.
Other Republican politicians are saying similar things, which will almost certainly be condemned by their opponents as incendiary at a dangerous time in American politics.
Already, we can see the battlelines being drawn in what may become a very ugly fight over a deeply shocking incident. And one that will reshape the election campaign.