Last week I wrote that America was a 49% nation, equally divided between the parties, as indeed it was in elections for the House of Representatives from 1996 to 2000 and in the 2000 presidential election.

I was wrong. George W Bush beat John Kerry by 51% to 48%. That does not sound like a large margin — but it is when you consider the circumstances.

Bush was not running, as most winning incumbents do, in a time of peace and prosperity. Americans are in the midst of a war, admittedly of an unfamiliar kind — and although unemployment and inflation are both low, there have been job losses since 2000 because of the bursting of the dotcom bubble and the September 11 attacks.

Bush faced an implacably hostile old media led by The New York Times, the news pages of The Washington Post and the old-line broadcast networks CBS, ABC and NBC — which provided lavish coverage of violence in Iraq and the Abu Ghraib prison scandal.

In September CBS ran a story about Bush’s service in the Texas Air National Guard that was based on forged documents; in October The New York Times ran a story blaming Bush for the loss of a small cache of Iraqi weapons that, it turns out, were not there when US troops arrived.

In the circumstances it is notable that Bush won, and won unambiguously. Turnout, according to the latest figures available, was up 11% from 2000, a factor that was supposed to help the Democrats. But Bush’s record popular vote of 59m was 17% more than his popular vote in 2000, while Kerry’s 56m votes were only 10% more than Al Gore’s.

Bush’s party won up and down the line. Republicans gained four seats in the Senate and will have a 55-45 majority: no more tie-breaking by Dick Cheney.

They gained five seats in the House of Representatives and will have a 234-201 majority there, just one seat less than their high-water march after the 1994 elections.

The popular vote for the House seems (not all the returns have been tallied) to be 51% Republican, 47% Democrat — about the same as in 2002, when Bush’s job approval hovered around 65%.

Bush’s organisational and turnout machine, made up mostly of 1m volunteers, generated record Republican turnout in the battleground states — and in other states as well. Exit polls showed a 39% to 35% Democratic advantage over Republicans in party identification in 2000; in 2004 it was 37% apiece.

Bush also made progress with fast-growing constituencies — up from 35% to 44% of Hispanics and from 41% to 44% among Asians, as well as with Jews (up from 19% to 25%). Some Democrats have argued that increased voting by immigrants will make it impossible for the Republicans to win a majority: that does not seem to be happening.

America has ceased to be a 49% nation and now is a 51% Republican nation. And if 51% sounds low, consider a little history. The model adopted by Karl Rove, Bush’s chief strategist, for the Bush presidency, is William McKinley, who won the 1896 election over the prairie populist William Jennings Bryan by 51% to 47%. He was re-elected in 1900, as controversy swirled over American military involvement in the Philippines, by 52% to 45%.

McKinley and his successor, Theodore Roosevelt, put in place policies — the gold standard, prosecution of business monopolies, an expansive foreign policy — well suited to the surging industrial America of the day. The Republican party became the majority party until the depression of the 1930s.

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