US President Barack Obama today stands on the edge of history.
Defeat at the hands of Mitt Romney, his Republican rival for the White House, will deny America's first black president the chance not just of redemption after a bruising four years, but a bid for greatness.
History warns that only two-term presidents - Bill Clinton, Ronald Reagan, Lyndon Johnson - have the chance to make that leap. The one-termers - Jimmy Carter, George Bush senior - must face a long retreat before history looks at them afresh.
And Obama - who has never been accused of viewing himself as an ordinary president - has coveted greatness ever since he first eyed a move to Washington as a young politician in the Illinois state senate a decade ago.
No other US politician in modern times has dared risk the rhetorical flourishes and promises of hope and renewed faith in America's highest motives.
Defeat, therefore, promises a sting even more vicious than usual for the 51-year-old and the voters who still cling to the hope he embodied four years ago.
Those hopes reached their zenith on the still autumn night in Chicago's Grant Park four years ago as Obama and his family took the stage. He had just defeated veteran Republican Senator John McCain in an election that saw 64 per cent of eligible Americans cast votes - the biggest turnout in a hundred years.
"If there is anyone out there who still doubts that America is a place where all things are possible; who still wonders if the dream of our founders is alive in our time; who still questions the power of our democracy, tonight is your answer," he said. He moved many in the 200,000 crowd to tears.
That was 2008. In 2012, however, the questions remain for many Americans and the doubts about America's future have only intensified, such were the depths and pain of the Great Recession.
Win or lose today, it is hard to imagine Obama attempting such rhetoric now. His presidency, of course, faced the grimmest start. He took office with the economy in the worst shape in a generation and its vast free market beginning a long-term structural readjustment.
While Obama won praise for nudging the US away from depression by stabilising banks and rescuing the car industry, growth is tepid and millions of Americans are out of work.
Unemployment hovers around the 7.9 per cent mark and the US deficit - fuelled in part by his predecessor's decision to invade Iraq - has soared further to US$16 trillion. Any economic success has been a tough sell on the stump, then.
His other ambitious goals - historic moves to provide health care to the 40 million Americans without insurance, and rebuilding respect on the national security and foreign policy front - remain works in progress.
Despite the challenges - and his formidable 2008 mandate - Obama has failed to marshal the disparate forces of the US Congress, unable to reach out to prickly, contrarian Republicans or curb the pork-barrel excesses of his own Democratic lawmakers.
The politics of peace and inclusion - highlighted by his former campaign cries that there was "no blue America and no red America" - have run aground on the reef of partisanship.
His administration has been dominated by the hard-boiled Chicago operatives who helped him win a spectacular victory but appeared ill-placed in the White House.
In this regard, he failed to heed the message of two-term Republican president Ronald Reagan, a figure whose stature and impact Obama has repeatedly acknowledged.
Reagan selected staff from rivals and had a balance of moderates, such as James Baker, his first chief of staff, to limit the impact of more conservative figures. He also forged a genuine friendship with the formidable House Speaker Tip O'Neill, an unabashed liberal Democrat whose views were the polar opposites of his own.
Obama has presided over a very different Washington and, at times, has appeared to have been shaped by it, rather than the other way around.
The result has been an ugly, gritty campaign. If Obama kept to the high road four years ago, this time he and his machine were prepared to tread a lower path, at times turning the race into a political street fight.
Even when Romney was struggling to see off his Republican primary rivals, the Obama campaign was targeting the former Massachusetts governor and multi-millionaire businessman with waves of aggressive television advertising.
"On a certain level, I take my hat off to them," said one Republican strategist. "They completely shaped Romney as politically unreliable and the worst kind of capitalist in the minds of the American people before he had a chance to present himself.
"It was hard but brilliant…that is why that first debate was so important to Romney, he had a chance to portray himself as at least human."
If Obama wins today, he added, it would demonstrate a rough kind of political greatness in itself. "He's shown he can win well, and he can win badly … politics is a tough game. The question will be then how can he apply the lessons to a second term."
The focus on Romney means that Obama has been criticised for having failed to sell his own record, as well as his plans for a second term.
A range of presidential scholars and analysts have been appalled at the wider campaign, pointing out that neither candidate has seriously attempted to level with the American people. Romney has faced intense criticism over repeated dishonesty in his advertising.
The irony is that real choice is on offer. Romney is promising tax cuts and more defence spending while somehow eking out significant reductions in the deficit.
He has yet to spell out precisely how, beyond shrinking the size of the government and targeting Obama's health-care reforms, as well as trimming federal programmes such Medicare, which covers senior citizens.
Obama is plotting his own budget cuts - including to defence - but will raise taxes on wealthy Americans. He wants to expand government support to the economy, funding more teachers and giving tax breaks to firms that keep workers in the US, while penalizing those that send jobs overseas.
Amid the bloated rhetoric and bitter campaigning, the hope still flickers among African-Americans that Obama will get a second term.
"They've called him a socialist and questioned his birth … He's had to work so much harder to get people to see him straight," said DC resident Joe Loving, aged 72. "They're finally accepting him as president on his merits now, so I say give him another chance ... I tell you, you could cut my legs off with an axe and I would hobble on bleeding stumps to get to the booth to vote for the man."