We are on the brink of history. On Tuesday the US could elect its first ever blue president.

The fact that Barack Obama would also be the first black president has obscured the significance of his political colouring. If he wins, he will be the first northern, urban liberal to win the presidency since the culture wars broke out in the US in the 1960s.

For the past 40 years, cultural conflicts over race, religion, patriotism and the permissive society have gradually divided America into Republican “red” states and Democratic “blue” states. There have been three Democrats elected to the presidency since the mid-1960s – but Lyndon Johnson, Jimmy Carter and Bill Clinton were all white southerners, whose cultural heritage blunted the sharpness of the division between red and blue America. Their states – Texas, Georgia and Arkansas, respectively – all went for George W. Bush in 2004. Mr Obama, by contrast, is a college professor from Chicago with one of the most liberal voting records in the Senate. He is blue America personified.

He shot to prominence at the Democratic convention in 2004 with an inspiring speech that denied the significance of the red-blue divide. But this year’s election campaign has confirmed that the culture wars are, in fact, alive and festering.

This has been an exhilarating and exciting contest. But the visceral dislike between red and blue America has also made it disturbing. There is talk that if Mr Obama loses on Tuesday there will be riots. And there has been plenty of raw anger on display at McCain rallies – with accusations that Mr Obama is un-American or linked to terrorists.

This toxic atmosphere is not the fault of the two main candidates. Although it is an article of faith among Obama supporters that Mr McCain has fought a dirty campaign, in one critical respect the Republican has held back – he has refused to make an issue of the racially incendiary sermons of the Rev Jeremiah Wright, Mr Obama’s long-time pastor and spiritual mentor.

Early in the campaign, a Republican operative joked to me that, by election day, most American voters would think that Rev Wright was Mr Obama’s running mate. In the event, it was only at the very last minute that Republicans in Pennsylvania ran advertisements that focused on the railing reverend. Mr McCain’s refusal to play the Wright card was an honourable act of self-restraint.

But the fact that the 2008 campaign has still been so bitter – despite the better instincts of two well-intentioned candidates – is all the more worrying. The diehards of red and blue America seem to deny each other’s legitimacy. This denial is there in the suggestion of Sarah Palin, Mr McCain’s running mate, that she represents the “real” America. It is there in the hatred of American liberals of the Bush administration and all it stands for.

It is odd – as a foreigner – to witness these bitter divisions in America. When I was at school, the conventional analysis was that it was Europe that bred political extremism and the US that benefited from the stability of a broad, centrist consensus. The joke in Britain was that the Republican party was a bit like the UK’s Conservative party – and so was the Democratic party. Both were committed to capitalism at home and anti-communism abroad.

But now it is Europe that is the continent of cosy consensus. In Britain, France and Germany, politics is dominated by centrist parties committed to similar principles – a welfare state and a social-market economy. Because Europe is now much more secular than the US, there is also no equivalent of the bitter arguments about abortion in America.

But the blue-red division in America goes well beyond religion. It also reflects different attitudes to military force and therefore to America’s role in the world.

The blue-red divide is also between urban and rural America, between coastal and inland America and between the educated and the uneducated. The big American cities will turn blue again on Tuesday and so will the coastal states. Most of Middle and small-town America is likely to stay red. To an extent that should truly disturb the Republicans, educated Americans will flock to the Democrats. Mr Obama has a 28-point lead among Americans with a post-graduate degree.

Ever since 1968, when Richard Nixon won the White House partly by campaigning against snobby, east-coast elitists, there has been a fear in blue America that they are a minority in their own country. At this year’s Democratic convention, the party was careful to pay homage to the totems of red America – in particular, the military.

If Mr Obama wins on Tuesday – particularly if he wins big – blue America will be tempted to believe that it has won the culture wars. There is already much happy talk about the construction of a new, liberal majority based on the country’s changing demographics.

But that would be the wrong conclusion. The one point in the 2008 campaign when the momentum switched to the Republicans was when Mr McCain nominated Ms Palin and chucked some red meat to red America. The cultural card was working for the Republicans until Lehman Brothers collapsed.

When the political conversation switched to the economy, the Obama campaign regained its strength. The economy has been Mr Obama’s friend during this campaign. It would become his enemy the moment he stepped into the Oval Office.

gideon.rachman@ft.com

Post and read comments at Gideon Rachman’s blog

More columns at www.ft.com/rachman

Get alerts on Columnists when a new story is published

Copyright The Financial Times Limited 2019. All rights reserved.

Comments have not been enabled for this article.

Follow the topics in this article