“I feel no need to kiss the ring. And I have no fear of Trump’s retribution, I’m not looking for anything from him,” she said earlier this year, criticising the “herd mentality” of her fellow Republicans.

She also pitched herself as a new generation candidate, compared to 81-year-old Biden and 77-year -old Trump, calling for mental competency tests for both and warning voters about the latter: “Everywhere he goes, chaos follows him.”

Having lost the early primary elections and then lost to Trump again on Super Tuesday, the biggest primary nominating contest of the season, Haley suspended her campaign on March 7 and urged Trump to earn her supporters.

Many of those supporters still continue to vote for her in primary races despite the fact she is no longer a candidate.

Earlier this month, for example, she won 21 per cent of the vote in Indiana and a further 20 per cent of voters in Maryland, signalling ongoing discontent with Trump, who is currently on trial for falsifying business records ahead of the 2016 election.

“I stand by what I said in my suspension speech,” Haley told the audience in Washington on Wednesday (Thursday AEST).

“Trump would be smart to reach out to the millions of people who voted for me and continue to support me and not assume that they’re just going to be with him. And I genuinely hope he does that.”

Haley is now the most high-profile former presidential candidate to back Trump. Only three other Republicans who also sought the nomination – former vice president Mike Pence, former New Jersey governor Chris Christie and former Arkansas governor Asa Hutchison – have not.

Insiders had long believed Haley would be forced to endorse him before the election to avoid permanently alienating the Republican Party base.

Others have speculated on whether she would re-emerge on Trump’s long list of vice presidential contenders in the coming months, despite his previous statement to the contrary and Haley earlier insisting this was “off the table”.

“Nikki Haley is not under consideration for the VP slot, but I wish her well!” Trump wrote on Truth Social earlier this month.

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