Watch as Republican vice presidential nominee JD Vance campaigns in Pennsylvania

Watch as Republican vice presidential nominee JD Vance campaigns in Pennsylvania on Saturday 21 September.

He will be making a stop in Berks County hours after rival Democrat Tim Walz spoke from the city of Allentown.

The pair will face off next month in the only scheduled US vice presidential debate, a chance for each man to reinforce his running mate’s message to voters just weeks before the 5 November election.

The 90-minute discussion, hosted by CBS News, will take place on Tuesday 1 October at 9pm ET in New York City, a Democratic stronghold that is the former home of Donald Trump, the Republican presidential candidate.

Ground rules for the debate are not yet public. At the September presidential debate, the candidates’ microphones were muted when it was not their turn to speak, and there was no studio audience.

Mr Vance, a US senator from Ohio, will have to work hard not to be on the defensive throughout the debate if Mr Walz employs his running mate Kamala Harris’ debate strategy.

He likely will face questions about his inflammatory rhetoric and could punch back with his typical combative style.

On the campaign trail, Mr Vance has portrayed Mr Walz and Ms Harris as radical liberals. He also has questioned Mr Walz’s depictions of his military record and his family’s fertility struggles.