IN his acceptance speech after winning a second term, Barack Obama returned to one of his favourite themes: that the partisan divide in the United States has been overstated.

"I believe we can seize this future together," he said, "because we are not as divided as our politics suggest. We're not as cynical as the pundits believe."

He has been delivering different versions of the same speech since 2004, when he first came to national prominence at the Democratic convention in Boston. On the night of his re-election, it was less true than ever. Perhaps in the morning, confronted with a map blue at the edges and dark red through the middle from top to bottom, he may have reflected that he is the president of two countries, not one. After an election campaign that cost almost £4 billion, the only states to change their allegiance were Indiana and North Carolina: both traditionally conservative states Mr Obama won by narrow margins four years ago and could not hold. Nationally, the popular vote was split 51% to 48%, with Mr Obama winning just three million more votes than Mitt Romney.

The two Americas exist side by side within states, of course. Exit polls showed Mr Obama's coalition is young, diverse, urban and predominantly female – and growing rapidly. The Republican party's is older, whiter, suburban and rural – and shrinking as a share of the electorate.

Niche media, catering to hardline conservatives and liberals, has supplanted balanced journalism: one America watches Fox News, the other MSNBC. One America listens to Rush Limbaugh, the other to National Public Radio.For four years, the right wing has portrayed Mr Obama as a foreign-born, un-American Muslim radical at worst and an incompetent product of affirmative action at best, promoted above his abilities by a condescending liberal elite. This caricature will not disappear overnight. On Fox News, Sarah Palin proclaimed Mr Obama's victory a "catastrophic setback" for the United States. Her colleague Bill O'Reilly lamented that "the white establishment is now the minority. It's not a traditional America anymore".

The New York Post, which had openly campaigned for Mr Romney on its front page, printed a sour grapes editorial: "It's not a mandate. It's a second chance."

The President will return to the White House with fewer illusions about the possibility of post-partisan compromise in Congress, after a first term that taught him Republicans are determined to thwart his agenda at any cost.

The Senate will be a little more liberal, thanks to the Democratic party's surprisingly strong showing, picking up Republican seats in Indiana and Massachusetts, and holding others they were expected to lose. New senators Elizabeth Warren and Tammy Baldwin are both to the left of the moderates they replace. In the House of Representatives, Republicans were able to hang on to their majority. Texan Congressman Pete Sessions said the result was a clear victory for conservatism: "Our House Republican candidates listened to the American people and rejected the Democrats' tax-and-spend agenda that threatens the American dream," he said.

Bush tax cuts for America's wealthiest are due to expire in January, along with a payroll tax cut that benefits many more middle-class voters. If the two sides cannot agree on a deficit reduction plan, the automatic "sequester" contained in the 2011 Budget Control Act will trigger deep cuts to spending.

Mr Obama is certain to insist the rich pay more and will offer spending cuts in return, but the Republican Speaker, John Boehner, has signalled his unwillingness to compromise. Congress, and the nation, are as divided as ever.