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Mental strength and the timing of a Covid vaccine could determine who is the next president of the United States.
Record Covid deaths, a late Supreme Court appointment and another high-profile Republican endorsing Democrat Joe Biden have made it a big week in US politics just over a month from the presidential elections.
But University of Otago international affairs specialist Professor Robert Patman is picking that, while Biden has the edge in polls, a close race could come down to a couple of unknowns.
"President Trump may be able to pull a rabbit out of a hat if he can produce a vaccine," Prof Patman says.
"The other thing we don't know is how Biden will perform in the presidential debates.
"Trump . . . is mentally quick on his feet. And I'm just wondering if Biden can stand up to that."