Only in America. Tonight, or early tomorrow if John McCain makes a close race of it, the world will learn who is to be the 44th US President. And, unless we are about to witness an upset that would make Harry Truman's comeback win in 1948 against Thomas Dewey look routine, that person is expected to be Barack Obama.

At this brief moment of calm, when the campaigning is over but the result is not known, it is worth stepping back to consider just how amazing the event would be. At one of the most difficult moments in its modern history, the US seems about to reach not to a grizzled senator or governor, not to a general or a businessman – but to a new and dazzling political talent who was virtually unknown barely four years ago.

Of course, Mr Obama has been fortunate. He ran in a year that even before the financial meltdown was always going to be difficult for Republicans. His marathon 50-state primary battle against Hillary Clinton meant he had a solid organisation in place across the country well before the general election campaign began. Indisputably, he has also had a gentler ride from the media than Mr McCain. But gifted politicians make their own success. Over the past two gruelling years, we have learnt a great deal about Mr Obama. He is formidably intelligent. Unlike the "tested" Mr McCain, he did not become rash or flustered at difficult moments. The three candidates' debates showed he is poised and collected under pressure. It was said of Franklin Roosevelt, one of America's very greatest presidents, that he had a second-rate intellect but a first-rate temperament. On all the available evidence, Mr Obama is top class in both departments. And by now the "inexperienced" tag has become somewhat worn. Yes, assuming he is elected, he will bring a thinner CV to the office than perhaps any president in history. But the past two years have tested him mightily.

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Mr Obama has never run anything, it is said. Not true. He has run arguably the longest, the biggest and the best organised campaign ever. Its discipline has been astonishing – in contrast to the campaign of Mrs Clinton that was once supposed to sweep all before it. And he has taken on the Democratic Party establishment as represented by the Clintons. In two years, Mr Obama has not made a major blunder. Yes, he has had a dedicated, top-notch team around him. But that too augurs well. Clearly, Mr Obama knows how to put the right people in the right jobs, a vital part of being president. And then, of course, he has style. Not since JFK will America have had as charismatic and inspirational a leader. Charisma and soaring oratory do not guarantee good government. But America is demoralised, exhausted and broke. It needs to turn the page on its recent past. And for that, it needs words, as well as deeds, to inspire it.

The election of Barack Obama will be a gamble. He may prove a disappointment like Jimmy Carter – another leader who emerged from nowhere, full of good intentions but overwhelmed by the job. There is no knowing. Nothing quite prepares a man for the presidency.

What is certain is that Mr Obama provides excitement, a desperately needed jolt of political electricity. If he is elected, America will instantly be seen in a new light around the world – not just because the unloved George Bush is gone, but because the country has found it within itself to turn to someone truly new, whose astonishing ascent could have happened nowhere else on earth. Only in America.