Trump hits 78 as age becomes pivotal in US presidential race

Donald Trump has turned 78, a milestone that will remind US voters that the two major-party candidates running for White House this year are the oldest ever to seek the office.

Age and mental sharpness have been at the centre of the contest between the Republican Trump and his Democratic rival, President Joe Biden, often getting more attention than substantive policy issues in the run-up to the November 5 election.

Public opinion polls show Americans are more worried about the advanced age of Biden, who is 81. But at 78, Trump is just three-and-a-half years younger and he would be the oldest person ever to be inaugurated if he wins a second term.

On Friday, Trump is scheduled to speak at a birthday party organised for him in West Palm Beach, Florida, by a group of staunch supporters called Club 47 USA.

On the campaign trail, Trump has not explicitly made an issue of Biden's age, but has sought to capitalise on his opponent's every verbal mistake, as well as Biden's slowing gait, to cast him as unfit for the Oval Office.

"It's not about age, it's about mental competence," said Trump campaign spokesperson Karoline Leavitt, arguing that voters can see the contrast between Biden and Trump, whom she described as "sharp as a tack with elite stamina."

Biden has responded to questions about his age by telling voters to focus on his accomplishments in office as evidence of his acuity and strength.

He has also described Trump as a threat to democracy following his efforts to overturn the 2020 election and criticised his sometimes rambling speeches, as well as his use of rhetoric against immigrants.

In a Reuters/Ipsos poll in February, some 78% of respondents - including 71% of Democrats - said Biden, already the oldest president, was too old to work in government. Some 53% of respondents said Trump, who was president from 2017-2021, was too old for government work.

Presidential historian Timothy Naftali said Trump projects energy in his public appearances, making him appear to be more vital physically than Biden, but that does not mean Trump is sharper mentally.

"It's not clear listening to the two men who is in better command of his faculties," Naftali said.

Neck-and-neck fight

Trump and Biden are neck-and-neck in national opinion polls, with Trump ahead in several of the battleground states that could decide November's contest.

It is unclear to what extent age will be a factor in the final outcome. Among issues that voters will be weighing is the strength of the economy, which overall is performing well but is beset by inflation.

Voters also have Trump's legal troubles to consider. Last month, a New York jury found him guilty of falsifying business records to cover up a payment to an adult movie actress on the eve of the 2016 election. He faces three additional criminal cases, though none are likely to go to trial before the election.

The first televised debate on June 27 will be an important test for both Biden and Trump, with voters looking for verbal slip-ups as a possible indicator that they might not be up to the task of leading the country.