Joe Biden and Donald Trump go live in Atlanta tomorrow afternoon, New Zealand time. 

The televised US election debate is the earliest in the campaign since 1960, with Americans going to the polls in just over four months. 

It's the third time the US President and the former President will go head to head after two heated encounters in 2020.  

The Spectator's Washington Editor Amber Athey  says the debates don't have as much sway on voters as most pundits would like to believe they do.  

She told Mike Hosking that this one will mostly be about showing who's physically and mentally fit to be President. 

Athey says so long as you can get through it relatively successfully, not much will change where voters stand on the candidates. 

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