A non-unionised car parts supplier just outside Detroit hosted the former president on Wednesday in primetime rather than the televised Republican debate in California.

As a sitting US president during a strike in modern times, Mr Biden on Tuesday glad-handed United Auto Workers (UAW) members near Motor City.

The red-shirted car workers on the picket line in the Detroit suburb of Wayne this week had little idea what’s driving these back-to-back visits by the two men most likely to face-off in the 2024 polls – attempts to claim votes in what is expected to be a key state in that contest.

Ford worker Tony Branner, 38, said he had voted for neither candidate in 2020.

Until now, he had not paid much attention to the election campaign.

The two rivals were practically at his doorstep, so he was prepared to listen.

“I will support anyone who fights to make my job better,” he said. I look forward to hearing what both of them have to say.” Mr Trump’s visit is a reminder of his success in winning over many mostly white working-class voters who felt ignored and left behind by mainstream politics.

According to exit polls, Mr Trump won four in ten union members in the 2020 election – a record for a Republican.

Mr. Obama presented himself on Wednesday evening as the saviour of the US auto industry, warning against Mr Biden’s efforts to tilt the industry toward electric vehicles.

“He wants electric vehicle mandates – that will kill the US auto industry,” he said. The cars will all be manufactured overseas.”