Donald Trump arrived in Milwaukee yesterday, ahead of a vote later this week that will confirm him as the Republican presidential candidate, after surviving an apparent assassination attempt which further boosted the stakes of what had already been heightened in the US political scene.

President Joe Biden has ordered an investigation into how a 20-year-old man carrying an AR-15-style rifle was able to get within shooting distance of Trump on a rooftop on Saturday. As a former president, Trump has lifetime protection from the Secret Service. The incident took place while Trump, 78, was holding a campaign rally in Butler, Pennsylvania -- one of the states tipped to be crucial for the election on November 5. Shots were fired, with a shot penetrating Trump's right ear, leaving his face bloodied. His campaign stated that he is recovering well.

That reality is just setting in," Trump told the Washington Examiner. "I rarely turn my back to the crowd. And had I not, in that instant, we would not have been talking today, would we?" One person in the crowd was killed and two others were wounded by his attack before Secret Service agents shot the suspect dead.

Both Trump and Biden called for calm and unity Sunday. Trump, who is expected to formally accept his party's nomination from the Republican National Convention on Thursday with a speech, went out of his way to say the speech would be far different than most had been anticipating. Biden spoke to the nation from the Oval Office, denouncing the violence but trying not to inflame an already overheated political situation.

There was a call Saturday night between Biden and Trump following the shooting, and First Lady Jill Biden spoke to Melania Trump Sunday. Opinion polls, including those by Reuters/Ipsos, point to a close 2024 rematch between Biden, 81, and Trump.

The FBI said there were no known threats to the Republican convention, which gets underway on Monday, and the Secret Service had no predicted changes for their security plan. Being staged at the convention are speeches by rising Republican stars and the announcement of Trump's vice-presidential running mate, addressing abortion, immigration, and the economy.

The FBI reported that Thomas Matthew Crooks of Bethel Park, Pennsylvania acted alone. At 20, Crooks worked as a dietary aide in a nursing home. The Federal Bureau of Investigation found no links to any ideology and reported he did not have any mental health issues. His father legally purchased a rifle used in the attack.

The Secret Service denied an accusation that it turned down a request from Trump's campaign to increase his security. Instead, the agency said it had recently increased the former president's security detail. The GOP chairs of the House Oversight Committee invited Secret Service Director Kimberly Cheatle to testify on July 22.

Butler County Sheriff Michael Slupe explained the response of the law enforcement involved in connection with the shooting. He said no information had trickled down to the officers that the suspect was armed. The shooter opened fire after the policemen who were trying to get onto the rooftop confronted him.

Corey Comperatore, 50, of Sarver, Pennsylvania, was killed defending his family. Two others were wounded but stable. Residents of Bethel Park say they are stunned by the news and think of rising political violence across the country.

This assassination attempt is the first shooting of a U.S. president or major presidential candidate since the 1981 attempt on Ronald Reagan. Many are concerned, with nearly two-thirds of respondents in a May Reuters/Ipsos poll saying they were concerned about violence related to the election. The incident brings to mind what happened following the riot at the Capitol on January 6, 2021, which left several people dead, after Biden's win over Trump in the 2020 election, as propelled by Trump's unfounded claims of far-reaching voter fraud.