Nonetheless, the genius of the Obama campaign – and the candidate himself – was recognising that a confluence of events over which he had no control himself had created conditions for a presidential run that were unlikely to reoccur in such favourable circumstances as in 2008.

Political campaigns happen in particular places at particular times
The factors that helped Obama win in 2008 did not exist in 2004 and may not do so in 2012 or 2016. This was his moment. Who was he running to succeed and who was he running to beat? Both matter.

The impact of George W Bush's problematic Presidency – war, natural disaster, financial crisis – was felt in both parties. On the GOP side of the aisle it poisoned the Republican party's brand; on the Democratic side of affairs, it persuaded liberals that desperate times required desperate measures. The case for "change" rested in large part upon the previous administration's inadequacies. But the scale of those setbacks also permitted voters to ask what "change" really meant and, having done that, consider which candidate seemed most likely to deliver a fresh start for the United States.

In one sense that was Hillary Clinton. A female Commander-in-Chief would clearly represent something new and fresh in American political history. And putting a Clinton back in the White House would be one way of wiping the Bush years from the country's collective memory, making them appear an awkward and unwelcome interruption from one Clinton to another.

Except they weren't all good times. And Hillary's surname would, in the end, be a problem not the solution. Could a Clinton really offer real change? Only possibly. And wouldn't electing Hillary reopen wounds best left to mend in peace? In the end and in a sense, wouldn't choosing Hillary be a backward looking notion for a country that likes to think its natural gaze looks to the horizon?

Of course, this theory depended upon there being an alternative to Hillary who could trump the card she used to win the "change" trick.
Then Obama entered the race. Suddenly, the calculations were rather different. Electing a white woman might normally be considered quite daring. But it seemed, well, rather vanilla when compared to the excitement suggested by the idea of an African-American president.
Hillary no longer had control of the Change narrative. Her glass ceiling was good, but not quite high or tough enough.

Freshness helped too. Obama's not been around long enough for everyone to have become bored by him. Or, to put it another way, a culture that craves new sensations – and new stars – in almost every other sphere is also unlikely to suppose that decades of experience in public life constitute the best preparation for the Presidency. For some voters anyway, Obama's novelty has been a bonus, not a blemish. At least, neither Clinton nor McCain has made hay with his lack of years in the national spotlight. But even if they had, it would have been a simple matter for Obama to remind the electorate that this election concerned the future, not the past.

So Hillary retreated to the bunker marked Policy. Ordinarily this too might have been a sensible move and perhaps it was, this time, also necessary. But of course this time, the most important policy issue for Democratic primary voters was the War in Iraq. And by late 2006, Hillary found herself on the wrong side of that argument. More crucially, Obama was in synch with the mood of the electorate. As far as voters in the primaries were concerned Hillary's greater experience was countered by her misjudging the greatest policy issue of the day.

Consequently the argument shifted to "Who can beat the Republicans?"
Here again, Obama benefited from the Bushian shambles. Had the stars been less obviously aligned in the Democrats' favour, some voters might have been less prepared to take a chance on the young, black guy. The pot odds made the gamble worthwhile.

As did the match-up. It is far from clear that the Republicans have any grounds for regretting their eventual, if reluctant, decision to select John McCain. It is possible, perhaps, that Mitt Romney might have handled the financial crisis more effectively, but finding a Romney path to victory remains a tricky business even if he might just have managed to be the policy reformer the GOP needed. Someone to play Sarkozy to Bush's Chirac or Major to Thatcher.

The problem with McCain, however, was that his story, like Hillary's, was trumped by the possibilities suggested by Obama's. Again, novelty matters.

McCain was running on his character and biography as much as his opponent. The McCain campaign never managed to settle on its core message. Were Americans voting for a war hero, a wise and experienced leader, a reformer with a record or an unpredictable maverick? It was never quite clear. Or rather, at different moments any one of these might be the message of the day and never mind that they were not necessarily complementary messages.

If all Obama had to offer was a nice story, then logic demanded that McCain's own biography be considered equally irrelevant. If wisdom and judgment were the idea of the day, then a way had to be found of squaring McCain being "right" on the surge in Iraq with his having been, in most voters' minds, "wrong" on invading the country in 2003. And wasn't the "wisdom and experience" strategy undermined by the "maverick" line of argument? Mavericks, by definition, are unpredictable and hot-headed.

We should remember that McCain's choice of Sarah Palin, reckless and ill-vetted though it was, did not come out of thin air. It came because the campaign was failing. Palin was the long-shot gamble that might, with luck, change the game. For a few days it looked as though it would work. Alas, then the interviews began and McCain's judgment was fatally compromised.

The Palin pick was the result, however, of Obama's success. And again Obama's relatively skinny record helped him. He was, if not quite a blank canvas then a candidate on to whom voters of all colours and persuasions could project their own ideas. Throughout the campaign Obama's coolness, his steadiness, his calm created an air about the candidate that seemed to say to voters "Make of him what you will".
Hence, the feverish ravings of some on the right. They looked at Obama and saw a radical. A Chicago hustler who palled around with "terrorist" Bill Ayers and the Reverend Jeremiah Wright.

But most people didn't see Obama this way. Some, for sure, have swooned thinking the candidate rather too super-impressive. But rather more people have seen Obama as a law professor from one of the finest schools in the country.

It's easy to forget that one of the things voters found attractive about George W Bush was the calm he was supposed to bring after the turmoil and hurly-burly of the Clinton years. That desire burns even more strongly after eight years of the Bush administration.
Thoughtfulness and a measured approach are back in vogue. And what better way to draw a line beneath the past eight years than by endorsing a candidate who not only has these qualities but also, in physical, flesh-and-blood terms, offers a means by which to turn the page?

Still, I've been struck by how many people still presume that the United States won't vote for a black President. Everybody knows, as a friend put it to me recently, that America is an "irredeemably racist country." Well! I don't believe that, actually. Yes, it remains too difficult for minority candidates to win statewide offices, but change is afoot. It's 40 years since Martin Luther King was assassinated.
That's 40 years of racists dying and an entire generation of schoolkids who learn that King was perhaps the greatest American of the 20th century. The Civil Rights movement is the idea in history classes across the country.

America is a much different place these days. And we've just discovered, I believe, just how much everything has changed. There'll be plenty time enough to disagree with the policies of an Obama administration, but it's worth taking a moment to reflect upon the import and symbolism of this election. Obama's shown that he has a natural sense of timing and, of course, the willingness to exploit every opportunity that comes his way. Now this is his moment. This is his time.

MORE ON THE US ELECTIONS:

• Chicago parties for its new, home-grown President, Barack Obama

• Alex Massie: This is Obama's time

• Defeated John McCain pledges support to President-elect Obama

• US election graphic: How the states were won

• Slideshow: Obama and McCain give their final speeches

• Slideshow: Obama supporters react in Chicago

• How it happened: Scotsman live blog

• Video: Hillary Clinton pledges her support for Obama

• Voting system creaks during record turnout

• • Prime Minister 'looking forward' to working with Obama

• 'We are going to the White House!' - Obama's Kenyan family celebrate victory