One by one, Donald Trump’s defeated rivals for the 2024 Republican nomination took the stage to sing his praises at the party's convention on Tuesday night.

From his box just above the convention floor, Trump smiled at times as he watched his former opponents Nikki Haley, Ron DeSantis, and Vivek Ramaswamy voice their full support for his candidacy.

If there were any doubts that this was Trump’s party, Tuesday’s programming put them to rest.

“I’ll start by making one thing perfectly clear: Donald Trump has my strong endorsement, period,” said Ms Haley, the former UN Ambassador who posed the strongest challenge to Trump earlier this year.

She said Trump had asked her to speak at the event in Milwaukee in the name of “unity".

“For the sake of our nation we have to go with Donald Trump,” she told the crowd.

Ms Haley said in May that she would vote for the former president, but her headline speech on Tuesday was her most direct endorsement of the Republican nominee yet.

And when she declared her endorsement, Trump stood and clapped.

Ms Haley’s arrival, however, was not universally welcomed in the arena. There was a noticeable intake of breath as she acknowledged that she and Trump had their differences.

Some Republicans have struggled to forgive her for launching an aggressive campaign against their favoured candidate. Late in the race, she questioned whether Trump had the mental stamina to serve as president.

A smattering of boos greeted her as she took the podium, though they were soon drowned out by cheers and chants.

She deserves the booing, said Gregory Switzer, a conservative activist from Texas.

“She stayed in that race a lot longer than she needed to and dragged out the inevitable," said Matt Bumela, a delegate from Washington state who had predicted the booing. “And said things about Trump that were negative all the way up to the end.”

Ms Haley notably broke from Trump when she called for the US to continue to support Ukraine in its war with Russia.

When she later said she would vote for him in November, she said the former president would be “smart to reach out to the millions of people who voted for me".

On Tuesday night, she told supporters of hers who might be on the fence: “You don’t have to agree with Trump 100% of the time to vote for him – take it from me.”

“Tonight is our unity night,” said New Hampshire state Senator William Gannon, who had served as a delegate for Ms Haley. He believed Trump made the right choice to invite her to speak.

“I wanna win the national election,” he said. “It was a wise move to bring her in.”

The third-place finisher in the primary, Florida Governor Ron DeSantis, received a far more enthusiastic welcome from the crowd.

He touched on several conservative social issues, including diversity initiatives, which he said were “indoctrination”.

He urged the crowd to rally behind Trump – though they were already solidly behind their current nominee. “We cannot let him down, and we cannot let America down,” Mr DeSantis said.

He also took a swipe at Mr Biden’s age, an issue that is currently roiling the Democratic Party. “We need a commander-in-chief who can lead 24 hours a day and seven days a week,” he said.

Daniel Willis, the 25-year-old chair of the Delaware Young Republicans, said Mr DeSantis and Ms Haley did more than enough “to bridge the gap” with Trump supporters.

Lara Trump, Donald Trump’s daughter-in-law and co-chair of the Republican National Committee, hit a conciliatory tone, telling the crowd: “You don’t have to admit that you like everything that he tweets, but Americans were better off when he was in office.”

She added: “Last Saturday reminded us that we Americans must remember that there is more that unites us than divides us."

The rest of the night was devoted to the more common Republican campaign points, such as migrant crossings at the border, crime and an overarching commitment to defeating Mr Biden.

Ted Cruz, the US senator from Texas, said there was a “literal invasion” of the United States. Dr Ben Carson, who served in Trump's cabinet, accused Democrats of “shredding the Constitution".

Trump himself led a huge standing ovation for Madeline Brame, a woman whose son was killed in New York in 2018 and has since called for tough-on-crime policies.

Down on the floor, delegates said they were ready to move beyond the intra-party divisions of the primary and instead focus the party’s energy on President Biden.

“At the end of the day,” said Georgia delegate Pam Lightsey, “We’re all Republicans.”