After years of campaigning and debating, the outcome of who will lead the country out of a devastating health crisis and a deteriorating economic one will be decided.

November 3, or Wednesday for Australians, marks a fork in the road for the US and, arguably, the world.

Down one road is a Donald Trump re-election. It will likely see the continuation of a nation divided over how to deal with a global pandemic and a historic shift in foreign policy for the weakening powerhouse nation.

The other road, a Joe Biden win, could see a return to the relative stability of an Obama presidency - one that's more statesman-like and pragmatic in the face of tensions and disasters.

For Australians, thousands of kilometres across the ditch, the event and its potential impact on our future might seem a world away but international affairs experts warn the outcome could have major ramifications for Australia's long-term future.

Professor Wesley Widmaier, an international affairs expert at Australian National University (ANU), said the difference between the two candidates was stark when it came to Australia's relations with the country.

"If Trump wins, we will continue to have what I think is a confused, sometimes hot and cold, US foreign policy, which will pose a challenge to Australia," Professor Widmaier said.

"With Biden, I think you'll have a return to what Australia is used to."

But Professor Widmaier pointed out a Biden win is not necessarily a return to a cosy relationship between the countries either. Former leaders of the two countries clashed over trade agreements, like the TPP proposal, before President Trump ever took office.

"Biden is looking after America's national interests and those conflicts won't go away either," Professor Widmaier said.

A return to the way things were pre-Trump days for the US's foreign policy if Biden wins is also unlikely to happen, Professor Widmaier said. While Biden would shift away from Trump's "make America great again" rhetoric, it would only be a more subtle side step.

"It's not like there'll be a reset in a TV show where we forget that bad season," Professor Widmaier said.

"One of the signs [Biden] puts on his podium when he talks about economics is buy American. It's not America first, but it is buy American.

"One can imagine that American foreign economic policy will become, you know, a little bit more assertive under Biden because again you don't do a complete reset."

Dr Charles Miller, a political science expert at ANU, held a more grave view of this election's outcome, calling a Trump win "quite frightening".

"[If Trump wins] the linchpin of the global world order, which has prevented major wars from breaking out since 1945, that order is pretty much over and what replaces it could be quite frightening," Dr Miller said.

"The fears that many Americans have is that this could be the beginning of America's ... backsliding from democracy into something like an autocracy or a semi-autocratic country."

Both Professor Widmaier and Dr Miller explained President Trump had a tendency to cosy up to dictators more than democratic leaders because they reflected his authoritarian personality.

It's seen President Trump form "bromances" with Russia's Vladimir Putin, Turkey's Recep Tayyip Erdogan, Brazil's Jair Bolsonaro and even China's Xi Jinping before the trade wars and coronavirus outbreak occurred.

"A Trump victory solidifies the hold of the Republican Party on American politics and America's basically dissent into an authoritarian, highly nationalistic government," Dr Miller said.

"It means that Australia is going to be facing some very tough choices."

READ MORE:

Echoing Professor Widmaier's predictions, Dr Miller said a Biden win will see a sense of normality return for US-Australian relations rather than the erratic approach we've seen over recent years.

If the polls are wrong and President Trump remains in the White House for another four years, Dr Miller warned the very fabric of Australian society could change.

"If Trump wins ... we no longer really have a dependable, great and powerful friend that can guarantee our security," Dr Miller said.

"That will mean an Australian Defence Force that's much bigger, much more able able to take care of itself, that will mean intensive diplomacy in the region and it could mean much higher taxes or lower spending on other things that Australians might want, or both of those things.

"Generally, a more insecure and scarier world."