In less than a week, more than 100 million Americans will be casting their ballots in what is being described as the most consequential election since the 1980 contest between Ronald Reagan and Jimmy Carter.
Reagan’s victory heralded 12 years of Republican rule in which America asserted itself – if only briefly – as the world’s hyperpower following the collapse of the Berlin wall and the Soviet Union.
Three decades later, assumptions about continued US dominance, Russian weakness, and an American ability to contain China’s rise have been swept aside in a world that is vastly more complex.
Whoever prevails on November 8 will face some of the most testing national security policy challenges since the end of the Cold War, and possibly more challenging since the world is much more fragmented.
So how should Australians view such a date with destiny, and more particularly how should we weigh the consequences of a Hillary Clinton or a Donald Trump victory?
The short answer in both cases is: “with trepidation’’.
The more likely – by no means certain – result is that Clinton will prevail. But the fact that such an outcome can’t be taken for granted at this late stage reflects the extent to which the American political system has been disrupted, to use the word of the moment.
What has played out over a protracted primary season and during an interminable presidential campaign represents a bitter residue that has accumulated over many years. It signals that vast numbers of Americans have lost faith in the system.
Thus the contest has been framed as a struggle between the establishment, represented by Clinton the archetypal Washington insider, and Trump, the outsider, who has never held elected office and has contrived to break almost every rule in the political playbook.
Trump is the anti-candidate candidate.
The fact a deeply flawed contender remains competitive, according to the polls, underscores the extent to which a swathe of Americans are disaffected with the system.
Trump is leading what might be described historically as a "peasant’s revolt”, partly fuelled – whether rational or not – by deep misgivings about Clinton.
A significant proportion of the American electorate neither likes nor trusts her. That includes Democrats. Likeability in American politics is a priceless commodity.
Let’s not forget an unworldly George W Bush secured two presidential election victories against less likeable, arguably much better qualified, opponents in Al Gore and John Kerry.
From an Australian perspective, and for the rest of the world - apart from Russia and its allies - a Trump victory would be a disturbing development.
Trump’s bellicose and unformed views on trade, relations with China, immigration, how to solve the problems of the Middle East and a host of other issues portend a bumpy ride. It may even lead to an unraveling of American-led alliances that have served – and continue to serve – Australia’s interests.
President Trump would almost certainly moderate his positions under the burdens of office, but the early stages of a Trump reign would promise a period of uncertainty.
Even discussing the possibility of a Trump victory might seem like a waste of space in light of the forces arrayed against him, from women to minorities to the Republican establishment itself. But given America’s strange mood and the recent Brexit experience nothing should be excluded.
This is especially the case in an environment in which October surprises - served up by WikiLeaks - threaten to continue into November with the prospect of further damaging revelations.
The WikiLeaks campaign against a US presidential candidate is without precedent, especially as reasonable suspicion falls on Russian cyber hackers for supplying the raw material in the first place.
The latest revelation that a CNN contributor, now interim director of the Democratic National Committee had secretly briefed Clinton on likely questions in debates during the primaries will reinforce persistent criticism about the shonkiness of the Clinton campaign.
Her primaries challenger Bernie Sanders and his supporters have every reason to feel aggrieved by these revelations. In a Clinton campaign that is depending on turnout, this is an unhelpful development.
Not least of the unfortunate historical happenstances of the 2016 presidential election campaign is that no really credible candidate – Sanders put up stout resistance, but was never going to prevail - emerged on the Democratic side to challenge Clinton’s inevitability as her party’s standard bearer.
On the Republican side, Trump was able to overwhelm his establishment opponents, including Jeb Bush, the Republican old guard candidate and early front-runner.
This brings us to consideration of Clinton from an Australian perspective.
In Canberra, Australian officials are making no secret of their aspirations for a Clinton victory, while mouthing the usual platitudes about Australia being prepared to work with whoever prevails.
Foreign Minister Julie Bishop gave voice to Australia’s preference at the weekend when she expressed the view that a Clinton victory would serve Australia’s interests, while warning of the risks of a Trump ascendancy.
“She sees the US as having a global leadership role,” Bishop told the ABC. “Candidate Donald Trump does not. He sees the US as having got a raw deal from globalisation and he would focus more on domestic matters.”
Other members of the Australian foreign policy establishment have been less restrained. Kim Beazley, former Australian ambassador in Washington, has described the prospect of Trump prevailing as “terrifying”.
All of that might be the case, but Clinton would bring her own baggage to Pennsylvania Avenue, not least her poor judgement in not subjecting the Bush administration’s arguments for the rush to war in Iraq to closer scrutiny in her days on the Senate Armed Services Committee.
In contrast to Barack Obama, her 2008 opponent for the Democratic nomination, Clinton did not push back against the administration’s manoeuvrings to create an environment in which war became inevitable.
Clinton’s perceived hawkishness – if that materialises – would inject a new uncertainty into the global environment after a period during which an Obama administration has sought to avoid, where possible, military entanglements in its efforts not to do “stupid stuff”, in the president’s own words.
Australian foreign policy establishment would be well advised to proceed cautiously in endorsing a new Clinton foreign policy that might seek to distinguish itself from that of its predecessor by “muscling up” militarily.
The Washington Post reported last month that the foreign policy establishment in Washington was looking forward to Clinton presidency with “quiet relief”.
In that article the author quoted a former Obama adviser as saying that in Washington “there is a widespread perception that not being active enough or recognising the limits of American power has costs… So, the normal swing is to be more interventionist.”
An early test of a new and possibly more muscular Clinton foreign policy may well come in the Middle East, where the former Secretary of State and her supporters have made no secret of their belief that Obama could have done more to prevent a vacuum in Syria and Iraq subsequently filled by Islamic State.
Clinton might also be more inclined to challenge both China and Russia with unpredictable consequences.
In one important regard Australian policy would be well served by a Clinton presidency. She is an architect and proponent of a US “pivot’’ to Asia, recognising that the world’s centre of gravity has shifted inexorably.
Uncertainties in American policy, whatever happens this coming week, speak to the need for greater Australian self-reliance, as described in this year’s Defence White Paper with its emphasis on an enhanced maritime capability.
Finally, what Australian policymakers will need to bear in mind is that either Clinton or Trump will represent damaged goods when she or he take the oath of office. In the end the question for America, no less than its friends, is which of the two is less damaged.