For once, the cliché wheeled out by desperate politicians trying to terrify their lazier supporters into voting is no lie. This is indeed the most important American election of modern times. Indeed, it is arguably the most important single election of modern times.
From the fate of the Middle East, to the global scourge of terror and the threat of nuclear proliferation, to the economic and financial future of the world's greatest debtor nation on all these issues, the next occupant of the Oval Office must make decisions that will shape history. If that were not enough, the country, which chooses today between John Kerry and George Bush, is as divided as at any time in its history.
The differences that the candidates embody are not merely of policy but of values and culture. The division marks a line between two Americas. On the one hand stands the "Metro America" of the coasts and the great cities, internationally attuned and socially more liberal, worried about the decline in America's reputation in the world. Then there is what has been called "Retro America," socially conservative, happy to live in a continental nation sufficient unto itself, populated by "good guys" chosen by God. No prizes for guessing which America supports which candidate.
The division runs through states, towns, streets and even families, generating passion and argument as in few elections past. Election 2004 has given the lie to the old claim that Americans are an apolitical breed, scarcely bothered about the vote. Today, the turnout is likely to be higher than at any election since John Kennedy's narrow victory in 1960.
The contrasts extend to the personal. For the President, this election offers the prospect of the second term that eluded his father. Unencumbered by serious interference from the independent Ralph Nader, he has a chance of securing uncontested legitimacy, by winning the support of more than 50 per cent of his countrymen.
It is worth remembering that not since George Bush Sr in 1988 has a president won a majority of the popular vote. For all his brilliance as a campaigner, Bill Clinton had to be satisfied with mere pluralities, 43 per cent in 1992, and, to his disappointment, only 49 per cent in 1996.
As a campaigner John Kerry, often ponderous, often lacking the human touch, is not a patch on Mr Clinton. But victory would seal a comeback that would eclipse any feat of the Arkansas "Comeback Kid." It is worth remembering that, in December 2003, the Massachusetts senator was trailing the Democratic frontrunner Howard Dean by more than 30 points in the polls in New Hampshire, only weeks before the crucial first Democratic primary.
It is possible to argue that, in the foreign policy field, the differences between the two candidates are of style rather than substance. Yet, this year, style is everything. We are talking of how America is perceived in the world. Is it a country that, whatever its unique power, is prepared to work with others in a spirit of give and take, ready to make compromises and concessions ready on occasion even to admit that it might have made, dare one say it, a mistake?
Or is it America the Chosen, which can do no wrong, the America of "my way or the highway?" Not since Richard Nixon in his prime has a president been as polarising as the younger Bush. And while America has been divided equally between positive and negative poles, the world has grouped overwhelmingly around the latter.
Even Reagan did not match Mr Bush for unpopularity. As survey after survey of global opinion has shown, the prospect of four more years of Bush, Cheney and Rumsfeld at the helm of the world's lone superpower is dreaded across great chunks of the planet.
Alas the concern is not reciprocated. One need look no further than the abuse and ridicule unleashed by The Guardian newspaper's "Operation Clark County", in which British readers were invited to advise the citizens of a swing area of a swing state on how they should take into account the views of their concerned British counterparts and ditch Mr Bush. Fat chance.
But one consolation for Bush-haters is that another foreign intervention Osama bin Laden's video was greeted with, if anything, even greater scorn. It does not appear to have helped the President, as several Kerry aides privately feared. There are signs indeed that it may have harmed Mr Bush, reminding US citizens their relentless and ever-decisive commander-in-chief has failed to capture America's public enemy number 1.
Even so, Kerry supporters must have trembled when they read that Le Monde had endorsed their man. America may feel entitled to meddle in the internal politics of other countries, but woe betide the foreigner who attempts as much here even though the US election probably has more impact on many other countries (Britain not excluded, given the much disliked but pivotal Blair-Bush axis) than their own domestic votes.
Will a new administration change tack on Iraq? What about North Korea and how should Washington approach Iran and its evident nuclear ambitions, already shaping up as the next potential flashpoint in transatlantic relations?
Will there be a shift in the US approach to the conflict between Palestinians and Israelis? What of the Bush doctrine of pre-emptive (or rather "preventive") war? Will the next administration finally take global warming seriously?
What of US trade policy, the deficits that increasingly dislocate the world's financial markets, and whither the dollar? All those are questions that have a more direct and vital bearing on foreign countries than on the states of Ohio, Florida, Pennsylvania and the battlegrounds where election 2004 will be decided. Yet, despite the attention lavished on them by the candidates, those topics, of such concern to the rest of us, have scarcely been discussed on the campaign trail.
"Rip Van Winkle America," the wise Washington Post columnist Jim Hoagland wrote at the weekend, of a country embroiled in an election in which the two candidates, skirting around what was really happening in the rest of the world, have either reduced those issues to caricature, or not mentioned them at all.
Listen to Mr Bush, and you would believe John Kerry's first act in office would be to negotiate a ceasefire with Osama bin Laden, and his second to put Jacques Chirac in charge of the Pentagon. The Democrat has been almost as culpable, talking of the disappearance of 400 tons of explosives from a weapons dump near Baghdad as if it were the most important single event in Iraq in the past 18 months. The other conflict between Israel and Palestinians, which colours everything in the Middle East, has been passed over in near total silence.
But even if the terrorist attacks of 11 September had never happened, this would still be an election of immense domestic importance. Except here too voters have been treated to a procession of clichés and distortions from Mr Kerry's supposed ambition to nationalise the healthcare system and indulge in an orgy of tax increases the moment he enters the Oval Office, to the Democrat's charge that if American seniors were as ill-advised as to vote for the President, they would see their social security entitlements vanish in a puff of privatisation smoke.
Quite apart from the blatant misrepresentations, the shared scaremongering ignores the fact that a president Kerry would find it virtually impossible to get serious tax increases past a Republican-controlled Congress, and Mr Bush's ambitious designs would founder on the filibuster of even a Democratic minority in the Senate.
With their promises of healthcare improvements and tax relief for the mythical, all-embracing "middle classes", both Mr Kerry, and especially Mr Bush, have avoided the uncomfortable facts that matter.
The challenger continues to imply that rolling back merely the President's tax cuts for the very wealthiest will be sufficient to pay for major extensions in health care. Meanwhile the word "deficit" does not trip from Mr Bush's lips, even though unless something is done soon, America's system of social security and entitlements faces disaster when baby-boomers retire.
Unmentioned as well is the near certainty that whoever wins is likely to be called upon to nominate two, perhaps three, Supreme Court justices. The new president will shape the balance of the court for a generation, and hugely influence the social battles on religion, gay marriage, gun control, abortion and so on that so exercise Americans in this era of permanent cultural war. This president's juridical legacy may outlive his term in office for decades.
But today, Americans and foreigners alike can only wait. The higher the turnout, runs the conventional wisdom, the better for the Democrat. But conventional wisdom forgets this is the first election since 1972 fought during a time of war, the first to take place after global terrorism has struck on America's own soil.
But for Iraq, Mr Bush would be all but certain of re-election. His economic record has not been disastrous, visibly at least. Despite the mess in Iraq, he still enjoys a handsome lead over his opponent when it comes to the most important issue: who best can keep the country safe? Events in Iraq, however, and above all the President's obstinate refusal to admit the slightest error, have called into question his experience and judgement, the same doubts which nagged his candidacy in 2000.
Even so, today may produce no clear verdict. The prospect frightens even the most hard-edged operators a repeat of the 2000 fiasco only involving not one but several states, where lawyers take over.Once again, America so quick to extol the virtues of democracy to others would have failed to make its own democracy work. Unlike four years ago, the disappointed party might be less inclined to accept a judgment from the Supreme Court, divided like the population at large. If the world awaits this vote with trepidation, so too do many thoughtful Americans. Please, they say, let there be a clear-cut winner.
Some believe that, in the final hours, the race will break one way or the other. Conceivably, Mr Bush will be the victim, not the beneficiary of the eccentricities of electoral college the winner of the popular vote but loser in enough swing states to hand victory to Mr Kerry.