Bondi Partners National Security Advisor Mark Watson says US President Donald Trump is going to sleep a lot easier tonight than rival Joe Biden because he's connected with voters more effectively in Pennsylvania and Florida than Biden.

"Joe Biden made an enormous mistake by lacking clarity around his green credentials - trying to walk both sides of the street - saying one thing in one part of the country and another thing in the other," he said.

"People have to remember, Australia may be the largest coal exporter in the world but the US is the largest coal producer in the world."