Hello, this is democracy calling. Whatever you read in the coming months, the American primaries are not another transatlantic electoral fiasco. They are the opposite. They are a nation testing its potential leaders by openly arguing, wavering, splitting, befriending, feuding, cohering and ultimately validating. Would that other democracies did the same.

American foreign policy has endured its most terrible decade in postwar history, largely because Washington’s establishment lost the plot under a tidal wave of paranoia and self-regard. The more reason to champion what, every four years, is the best face that America presents to the world, its ever-refreshing way of changing its guard.

To ridicule American elections, or deplore them because they fail to yield a desired result, is the worst form of anti-Americanism because it is antidemocratic. If to lead is to set an example, American elections are leadership. Their essence is their unpredictability. A touch of anarchy is proof that they reflect the world’s most pluralist society. Nowhere does them better.

I once attended the Iowa caucuses, which this January attracted the usual bemusement on this side of the Atlantic. Groups of voters gathered in town halls, schools or each other’s private houses and solemnly debated whom they wanted as president.

They were visited by exhausted candidates or their aides. They were nudged, bounced, persuaded and corralled until they reached a decision. The process was remarkably free of acrimony and, as far as I could tell, of corruption. The quality of debate in this democratic ritual was high. It was like a meeting of early American Puritans.

These primaries are the nearest most voters come to influencing a presidential election, given that it is decided in just a few “swing” states. The candidates must perform before audiences across the nation, with sequential votes acting as a running temperature check on public opinion. The experience thus roughly approximates to the pressures and accidents of high office. It is trial by ordeal, as if the candidates were facing a grand jury for daring to commit larceny against the state, which in a sense they are.

The process is effective. On the Democratic side, two good candidates are rightly being forced to fight to a finish, the outcome as yet uncertain. Hillary Clinton’s smooth campaign was cruelly halted by Barack Obama’s astonishing February burst. Obama’s apparent rush to coronation was stalled by Clinton’s fightback in Ohio and Texas. The same process picked off John McCain’s Republican challengers, revealing the weaknesses of each under the glare of public inquisition.

This is not the politics of back rooms, lobbies and private interests. Primaries are not a byproduct of the wheeler-dealing of party clubs, as in Europe’s oligarchic democracies. This is extrovert politics at its most extreme.

Nor do the jibes made by Europeans apply, at least on this occasion.

Money is important in American politics but the survivors in the race so far, McCain, Obama and Clinton, are not personally rich. Their campaigns have been financed by prospect, not retrospect. Money is drawn to power, not power to money.

When so much about American democracy is murky, its signal qualities should be registered. The processes of its elections, warts and all, are what America should be trumpeting to the world, not its ideological sanctimony or its military firepower.

This is all the more true since today there is not one American president to be voted into office but two. One belongs to domestic America but the other belongs to the world.

The first president is America’s business. While those who know and love that country may be concerned at its economic and political health - and therefore intrigued by the contest - this president is the one most voters have in mind.

The globalised president is a different matter. This leader must represent America’s values - and consequent actions - everywhere that is touched by American policy. His or her decisions benefit or afflict millions of people, rich and poor, in dozens of countries on every continent. Yet they have no vote.

Iraqis, Afghans, Palestinians, Israelis, Pakistanis, Colombians, Brazilians, Russians, Chinese have no means of saying yes or no to decisions taken in Washington that may intimately affect their families, their security, their jobs and prospects. Nobody accounts to them or invites them to any caucus. Few of them enjoy democratic privileges even in their own countries. Yet the next president of the United States can mean life or death.

When I was in Pakistan recently, I asked a former army officer how he intended to vote in his forthcoming elections. He said he would vote for a religious party, an answer that surprised me. But it was, he said, the only way a Pakistani could vote against George Bush.

The man was expressing a now widespread aversion to America, especially in Europe and Asia. It is not usually an antagonism to Americans or to America’s democracy or culture. It is a response to aggressive policies with which many profoundly disagree yet over which they have no control, other than by punishing those they see as America’s collaborators.

I believe that this so-called “crisis of anti-Americanism” derives from nothing more complex than a bitter sense of disenfranchisement. For all the words spoken on globalisation, few are expended on accountability.

The greatest irony of modern history is that this sense of personal disempowerment, which the whole American enterprise was founded to correct, should now be directed against America itself. The arrogance of George III has become the arrogance of George Bush.

All three presidential candidates have qualifications to be this global president. In public statements they have acknowledged the strategic mistakes made in America’s attempt to police the world through a “war on terror”. All have proposals for restoring America’s relations with the world.

Leadership cannot exist if others will not follow. America cannot regulate the world under Bush’s banner that “he who is not with us is against us”. It does not work.

The candidates for the global presidency will not be judged by experience, programme, oratory or novelty. They will not be judged by the prospect of likely success in office, which is always unknowable in foreign affairs. Few American presidents are seen to have been successes on leaving office. The art of presidency is that of managing perceived failure.

The candidates will rather be judged by what they symbolise, by the package of expectations that they carry with them to the White House.

Here it is simply incontrovertible that the election of Barack Obama would transform, indeed electrify, America’s image worldwide. Monochrome would become colour. A drone of antagonism would turn into a cry of pleasure. With the genes of an Irish-American and a Kenyan, and the nurture of Hawaii, Indonesia and Chicago, Obama has personal roots in four continents.

In choosing a president for a world half of which America seeks to evangelise, voters could hardly find a candidate better cast. He embodies a yearning expectation of a new contract and a new beginning.

Obama’s novelty remains a strength and a weakness but there is no excuse for regarding him as shallow. Not only is he a serving senator but his elegant early memoir, Dreams from my Father, and his more recent The Audacity of Hope reveal a remarkably thoughtful and complex man with a gift for language and an acute sense of the world about him.

These books display no anguish in Obama’s ambiguous identity, but an awareness of its richness. He offers the calmest discussion of the politics of race that I have read. He is conscious of the tension between America’s battered interventionism and John Quincy Adams’s warning not to go abroad “in search of monsters to destroy”, nor to become “the dictatress of the world”. The issues are not discussed in the manner of an ingénue.

Obama’s published prospectus must raise expectations, especially abroad, that no president could possibly meet, but it gives his candidature a substance that I had not expected from his platform performances. They offer not the remotest justification for Clinton implying that he is a security risk.

All this may cut no ice among the famously pragmatic American electorate. In election year, voters have domestic concerns and they see the outside world through the far end of the telescope. But they should bear in mind that they are electing not one president but two. When they go to the polls, they carry with them the eager proxies of half the world.

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