Donald Trump, sombre and bandaged, accepted the GOP presidential nomination on Thursday at the Republican National Convention in a speech that described in detail the assassination attempt that could have ended his life just five days earlier before laying out a sweeping populist agenda, particularly on immigration.

The 78-year-old former US president, known best for his bombast and aggressive rhetoric, began his acceptance speech with a softer and deeply personal message that drew directly from his brush with death.

Moment by moment, the crowd listening in silence, Trump described standing onstage in Butler, Pennsylvania, with his head turned to look at a chart on display when he felt something hit his ear. He raised his hand to his head and saw immediately that it was covered in blood.

“If I had not moved my head at that very last instant, the assassin’s bullet would have perfectly hit its mark,” Trump said. “And I would not be here tonight. We would not be together.”

Trump’s address, the longest convention speech in modern history at just under 93 minutes, marked the climax and conclusion of a massive four-day Republican pep rally that drew thousands of conservative activists and elected officials to swing-state Wisconsin.

Sensing political opportunity in the wake of his near-death experience, the often bombastic Republican leader embraced a new tone he hopes will help generate even more momentum in an election that appears to be shifting in his favour.

“The discord and division in our society must be healed. We must heal it quickly. As Americans, we are bound together by a single fate and a shared destiny. We rise together. Or we fall apart,” Trump said, wearing a large white bandage on his right ear, as he has all week, to cover a wound he sustained in the Saturday shooting.

“I am running to be president for all of America, not half of America, because there is no victory in winning for half of America.”

While he spoke in a gentler tone than at his usual rallies, Trump also outlined an agenda led by what he promises would be the largest deportation operation in US history. He repeatedly accused people crossing the US-Mexico border illegally of staging an “invasion.”

Additionally, he teased new tariffs on trade and an “America first” foreign policy.

Trump also falsely suggested Democrats had cheated during the 2020 election he lost, despite a raft of federal and state investigations proving there was no systemic fraud, and suggested “we must not criminalise dissent or demonise political disagreement” even as he has long called for prosecutions of his opponents.

He did not mention abortion rights, an issue that has bedeviled Republicans ever since the US Supreme Court struck down a federally guaranteed right to abortion two years ago.

Trump nominated three of the six justices who overturned Roe v. Wade. Trump at his rallies often takes credit for Roe being overturned and argues states should have the right to institute their own abortion laws.

Nor did he mention the insurrection at the US Capitol on January 6, 2021, in which Trump supporters tried to stop the certification of his loss to Democrat Joe Biden. Trump has long referred to the people jailed for the riot as “hostages.”

Indeed, Trump barely mentioned Biden, often referring only to the “current administration.”

“It was Donald Trump who destroyed our economy, ripped away rights, and failed middle class families,” said Jen O'Malley Dillon, the Biden campaign chair, in a statement after the speech. “Now he pursues the presidency with an even more extreme vision for where he wants to take this country.”

The convention ends at an uncertain moment in the race.

With less than four months to go in the contest, major changes in the race are possible, if not likely.

Trump's appearance came as Biden, the 81-year-old Democratic incumbent, clings to his party’s presumptive nomination in the face of unrelenting pressure from key congressional allies, donors and even former President Barack Obama, who fear he may be unable to win reelection after his disastrous debate.

Long pressed by allies to campaign more vigorously, Biden is instead in isolation at his beach home in Delaware after having been diagnosed with Covid-19.

The convention has showcased a Republican Party reshaped by Trump since he shocked the GOP establishment and won over the party’s grassroots on his way to the party’s 2016 nomination. Rivals Trump has vanquished – including senators Ted Cruz of Texas and Marco Rubio of Florida, former UN Ambassador Nikki Haley and Florida Governor Ron DeSantis – put aside their past criticisms and gave him their unqualified support. (AP)