America's divided as it heads to the voting booths today.

LISTEN ABOVE: Speaking to Rachel Smalley is Mark McKinnon, host of Showtime’s The Circus – Inside the Greatest Political Show on Earth, advisor to production team of House of Cards, former advisor to George W Bush and John McCain 

American political advisor Mark McKinnon said the mood is ugly, most Americans aren't happy with either candidate, but one way or another they're going to have to make a choice.

He said in many ways he's more worried about the aftermath of the election than the result itself.

Mr McKinnon said Hillary Clinton's run a better campaign and will likely win.

But he told Rachel Smalley there's a big question as to how Donald Trump will respond, and what his followers will do.

"He's got close to half the country who support and are very angry and have a strong dislike for Hillary Clinton. A lot of them will feel that, as Trump suggested to them, that it wasn't a legitimate outcome."

Mr McKinnon said if Mr Trump doesn't run again, the question is whether he can transfer his brand and equity to someone else. 

Mr Trump has cast his vote in New York - the state Mrs Clinton looks tipped to win.

Newstalk ZB's Jack Tame said it's in the swing states - like Ohio, Florida, and Pennsylvania - that the election will be won or lost.

He told Rachel Smalley Mrs Clinton is trailing behind Mr Trump in Ohio, while in Florida it's neck-and-neck.

"North Carolina could be critical. If Hillary Clinton were to win North Carolina, Donald Trump's path to the presidency through the electoral college is very very difficult indeed."

Mr Tame said Pennsylvania is expected to hold strong for Mrs Clinton.