LONDON Maybe it hardly bears thinking about the morning of November 5 if Barack Obama has lost to John McCain the previous day. And it may seem perverse to think about it at all on a day like today, when Obama yet again commands the stage. But let`s try to do it, right now, partly because the closeness of the polls suggests a narrow McCain win is a real possibility - partly because there has been so much underlying nervousness, as well as renewed exhilaration, among Democrats in Denver this week; and partly just out of common political prudence.

So, why might McCain win on November 4? I think there are five main reasons to consider.

The first is that these remain insecure times. The economic downturn has been very real in the US, in spite of recent good growth figures. America`s fear of rising fuel prices remains a potent electoral issue, laced as it now is with the fear that high oil prices are lining the coffers of America`s enemies in places such as Russia, Iran and Venezuela. American soldiers are fighting difficult wars in Iraq and Afghanistan. McCain has a big poll lead on national security, foreign policy and ability to deal with a crisis. Every Russian tank rumbling around the Caucasus is harvesting votes for McCain - and the electorate may prefer to entrust the country to a leader with warrior credentials than take a chance on a visionary neophyte.

The second reason why McCain might win is that this election is no longer about George Bush. America in late 2008 has a president who is a member of the political living dead. His name was barely mentioned at the Democratic convention this week. Along with Dick Cheney he will make an early appearance at St Paul at the Republican convention; after that, he`s out of it. And with him may go many of his negatives. That leaves McCain some elbow room to fight the campaign his own way. McCain is a tough campaigner. He is also a smart one. He could do well in the televised debates. Compared with the midterms in 2006, the Democrats may find it hard to make this an election about Bush.

Which brings us to reason No 3. American presidential elections are always close these days. Bush beat John Kerry with just 51 per cent of the popular vote in 2004 and was neck-and-neck with Al Gore in 2000. In the electoral college Bush won by 286-251 against Kerry and by 271-266 against Gore. In the past four presidential elections - even the two that Bill Clinton won - no Democratic candidate has ever polled more than 49 per cent. Democratic landslides have not been in fashion since 1964. This year`s polls - in which Obama`s average lead is now just 1.8 per cent - are beginning to point to yet another 5050 election. In these close races discipline, negative campaigning, and get-out-the vote organisation in the battleground states all matter. Over the years these have been Republican strengths, not Democratic ones.

Recent polls also point to the fourth piece of good news for McCain voters may be suffering from Obama fatigue. Obama is still fighting a campaign that is centred on self. His own story, his own vision and his own uniqueness are at the heart of his message. He consciously takes the whole weight of the campaign on his own slim shoulders, as he did again last night by taking his acceptance speech out of the convention hall and into the local football stadium, where he spoke against a backdrop of Greek pillars. Hubris? What if the nation that fell in love with Obama in the first phase of his great campaign decides he is yesterday`s rock star as the real election nears. I think Obama is well aware of this - but voters don`t just want big vision and soaring oratory.

The final reason is simply Obama`s race. The nomination of a black man to be president is not something marginal but something massive. It goes to the heart of whether America`s self-identity is genuinely multiracial, or whether, in spite of everything, it is still white. This election isn`t just about the possibility of a black president, but the possibility of a black first family. It asks white voters to see themselves embodied and represented by African-Americans, and to vote to be led by black people. This is something bigger than electing a woman leader would be, were that on offer. Race and slavery are America`s original sin. The election of Obama would be, beyond question, one of the noblest gestures of historical redemption that Americans have ever been called upon to make. But that is precisely why it may not happen.

So if, on January 20 2009, it is McCain, not Obama, who stands in the winter`s air on Capitol Hill to be sworn in as Bush`s successor, what would that mean for America and the world? The first thing to say is not to exaggerate the domestic or even the international impact; McCain would be the president of an already humbled, not newly triumphalist, conservatism. The economy would dominate his agenda. The next, umbilically linked point is to remember that McCain would have to work with a Congress in which, on the same election day, the Democrats are likely to strengthen their majority in the House of Representatives and secure firm control of the Senate. He could very easily find himself a weak president.

Yet there could be no disguising the lessons for the Democrats, who would have lost three winnable presidential contests in a row. If Obama loses, there will not be another African-American nominee for at least a generation. Hillary Clinton might have the consolation that she would become, overnight, the overwhelming favourite to finally win the Democratic nomination in 2012. But who would bet against such a divisive figure not extending the losing streak from three to four? It would begin to look as if the only way of getting a Democrat into the White House would be as the result of an armed uprising.

All that would be as nothing to the global dismay that would greet the election of President McCain. Much of the world would simply despair of the American people - and so would many Americans. Anti-Americanism would have a new recruiting sergeant, and global confidence in the democratic progressive project would suffer a historic blow. November 5 would be a bonfire night of the liberal vanities. I tend to think it won`t happen that way - but it certainly could. And it may all be just 10 short weeks away. —Dawn/Guardian News Service