For all its overbearing confidence and famously self-focused view of the universe, it’s been a long time since New York played a central role in the outcome of a US presidential election.

Since the realignment of American politics that began in the 1960s, and the conservative ascendancy that followed, New York has been too liberal, too northeastern, too libertine even, for the strait-laced sensitivities of middle America.

The last New Yorker who looked like a serious contender was Mario Cuomo. Hamlet on the Hudson, as he was known, a silver-tongued orator and the state’s Democratic governor, famously agonised publicly for months over whether to seek his party’s nomination against George Bush Sr in 1992. As with Shakespeare’s Great Dane, the native hue of Mr Cuomo’s resolution was sicklied o’er with the pale cast of thought, and he let his moment pass.

Bobby Kennedy was an adoptive New Yorker when he ran for the presidency in 1968. His soaring potential was of course brutally downed by that depressingly familiar fixture in American sociopathy, tragically on display again this week, the crazed gunman with a grudge.

You have to go all the way back to Franklin Roosevelt to find a successful New York candidate for president. Even he didn’t quite fit what we think of in today’s terms as a New Yorker. The political geography of his Hyde Park home could have been transplanted from rural Ohio or Virginia.

Recently, New Yorkers have been fringe candidates — single issue people such as Al Sharpton, the Democratic firebrand black preacher, or Steve Forbes, the clever billionaire who campaigned for radical tax reform on the Republican side but whose eccentricities suggested flat earth more than flat tax.

But here we are, 18 months away from the next election, and the US presidential contest could pass for a heated debate between a doughnut and a coffee vendor in Times Square. The Democratic front-runner is Senator Hillary Clinton, some time Illinois native, Arkansas resident, Washington DC habitué, but who has made up for her out-of-state beginnings with a wholehearted embrace of the Big Apple.

On the Republican side, the current favourite, it seems, is Rudy Giuliani, New York City’s former Mayor. He is much closer to the popular image of a New Yorker than Mrs Clinton: garrulous, pugnacious, a mite eccentric, but his post-9/11 stewardship of City Hall lifted him into the front ranks of contenders.

Meanwhile, the city is abuzz with news that Michael Bloomberg, Mr Giuliani’s successor as mayor, is carefully tending his own aspirations. Should Americans grow bored with the long nature of the race, he thinks he could emerge as a third-party contender. I was amused to hear him address a conference in Washington last month on the somewhat heavy subject of American financial markets and their global competitiveness. The ambitious mayor quickly left the arid territory of financial regulation and capital market integration and ventured with passion into the lush political lowlands of immigration, education and growing inequality, a performance that prompted Robert Rubin, the former Democratic Treasury Secretary, sitting alongside him to quip that it looked like a presidential declaration there and then.

It all sounds like a New Yorker’s fantasy, or depending on your view, some sort of bad joke — the next election a three-way New York tussle between a Democrat, a Republican and a serious and wealthy independent. For good measure, in happy replication of the city’s complex ethnic and religious mix, a Protestant, a Catholic and a Jew to boot.

I suspect it will remain a fantasy, however. Mr Bloomberg’s ambitions are the longest of long shots and Mr Giuliani’s liabilities in the Republican Party — a firm commitment to socially permissive laws on abortion, gay marriage and other matters — still look likely to outweigh his not inconsiderable assets.

Mrs Clinton is a different matter, of course, but my conversations with a number of prominent New York Democrats this week suggest that, most remarkably, she too may be faltering in unexpected ways.

Throughout its years in the presidential wilderness, New York has still played an important role in the mechanics of Democratic presidential politics. The city — and to some extent New York state — is, to paraphrase what the famous felon Willie Sutton said to explain why he robbed banks, “where the money is”.

Despite its strong Republican connections, Wall Street has long been an important source of funding for the Democrats and their candidates. New York’s media elite and the professional plutocracy of the city that inclines strongly liberal in its political predilections further bolster Democrats’ bank accounts. So far this money has been funnelling towards Mrs Clinton in predictably large sums.

But that may be changing. One prominent New York Democratic rainmaker told me this week that in the past few weeks there has been a significant shift in sentiment towards Barack Obama, the black senator from Illinois, who has in the six months since he first declared his interest, steadily upended the Democratic race.

More and more Democrats seem to be willing to shed their doubts about Mr Obama’s inexperience — he is only 45 and has served in the Senate for just two years — and sign up for him. Opinion polls in the last few weeks have shown the gap between Mrs Clinton and Mr Obama closing.

The money is starting to follow — Mr Obama already raised more cash for the Democratic primary race in the first quarter of 2007 than did Mrs Clinton. The reason seems to be not so much the doubts some have about Mrs Clinton’s personality, but a powerful desire across the country for real change from the politics, not only of the last six enervating years of the Bush presidency, but of the last couple of decades.

If they are right Mr Obama may be catching a Zeitgeist that is not just American, but global. Voters in France this weekend will cast their first votes for their next president. If the polls are accurate, the clear favourite seems to be Nicolas Sarkozy, the former Interior Minister and a man whose policy prescriptions seem to promise a radical break with the widely despised Jacques Chirac, but also with the whole fabric of French politics and economics for the past 30 years.

In Britain, Gordon Brown’s biggest enemy is a similar desire for real change that could propel David Cameron’s Tories into office.

In New York, a powerful Wall Street figure summed up the mood like this: “People think Obama is where the world is today,” he told me. “Hillary is where the world was in the past.”

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