There are cycles in American political life, argued historian Arthur Schlesinger. Spells of conservativism and private purpose alternate with periods of liberalism and public-spiritedness. If the Schlesinger thesis has any validity, the United States looks as if another such transition is just beginning. One signal of change is that the opinion-poll leader for the Republican Party nomination, Rudy Giuliani, is a three-time married man who has marched in New York gay rights parades. Yet another is that the Democrat front runner is Hillary Clinton.

Behind these changes is a swing in the cultural pendulum. The key indicator is religion, always important in the United States. For the last 25 years, an evangelical, militant, right-wing Christianity has been making the political and cultural weather.

The high-water mark was November 2004 when nearly half the Senate and two-fifths of the House of Representatives could be claimed by the fundamentalists as fully bought into their agenda — from anti-abortion to anti-stem cell research.

Yet since then, the Christian right has found progress tougher, in part because of an embarrassing string of scandals, in part because secular America has begun to reassert itself and in part because a growing number of American Christians are uneasy about

allowing religion to become so politicised and so closely associated with one party. Fundamentalist Islam has also made a difference; it has reminded the bulk of Americans of the wisdom of the American constitution — keeping religion and state apart.

For two faiths coexist in the US: one is devotion to God and the other to the Constitution. Religion is a private matter, with which the state is barred from interfering and which is barred from interfering with the state. Fundamentalist Christians have had ambitions to overturn that long-standing convention.

For years, Democrats have unsuccessfully attempted to demonstrate that personal faith does not need to include the urge to evangelise the whole country. The wider mood has changed in their favour. The Pew Research Centre reported last July that 49 per cent of respondents thought that conservative Christians were going too far in imposing their religious values

on the country. The mood has been reflected by an extraordinary little book Letter to a Christian Nation by Sam Harris. It has become a bestseller.

Harris quotes passages from the Bible such as one in Exodus discussing the demands you should make when selling your daughter into slavery. One passage from Deuteronomy encourages Christians to stone to death anybody who tries to draw them away from their God. For a book which ridicules religion and ruthlessly exposes the inadequacies of the Bible to become a bestseller is a classic Schlesinger-style signal that times are changing. And politicians are feeling the mood swing.

Religion is not the only indicator. Other tipping points have been reached and exceeded; for example, the consensus that the US needs to act both individually and with others to limit the emissions of greenhouse gases. It seems, with a little under two years to go, that the Democrats have the presidency for the taking — just so long as they make no disastrous gaffes and read the cultural runes properly. — The Guardian