When Ed Koch was Mayor of New York in the 1980s he took to stopping voters wherever he went and asking them: “How am I doing?” Their reply was, in the most part, positive. His successor bar one, Rudy Giuliani, effectively wagered the whole of his presidential prospects this year on presenting Republican voters in Florida with a similar question. Their reply was conclusive, if not especially flattering. As a result, Mr Giuliani has raised and spent a fortune but in the space of barely ten weeks has moved from being the national front-runner for the nomination to being obliged to abandon the field, having won one solitary delegate for his expensive efforts. How did this happen? What does his fall mean?

In part, it occurred because his initial apparent strength was thoroughly misleading. A year ago, John McCain was the early favourite for the Republican crown and many analysts wondered if Mr Giuliani would be prepared to set aside his extremely lucrative career on the speaking and advisory circuit to launch an improbable bid for the Oval Office. He did and benefited when Mr McCain, demonstrating customary courage and contempt for expediency, called for more troops to be sent to an unpopular war in Iraq and supported a reform of immigration law that had much merit but few friends in conservative circles. He paid the price then, but has reaped rewards later. Mr Giuliani, the only other well-known Republican at that stage, assumed his mantle. It was, though, an illusory status. It had yet to be tested where it counted, in the white heat of elections.

It is a further tribute to this compelling, extraordinary and quite wonderful caucus and primary season that when that moment came, ordinary Republicans took another glance at Mr Giuliani and decided that he was not the man to be their champion. He had undoubted achievements as Mayor of New York City - on crime, welfare reform and reducing taxes - but the Big Apple is not New York State overall, never mind the rest of the United States. The qualities required for the presidency are different and more subtle and Mr Giuliani's evident authoritarian streak, his choice of associates and dubious ethical standards would not have been appropriate. He might have had vastly more campaign funds than Mr McCain a few months ago but of itself that was and is not a qualification for high office. Floridians have, thus, done Americans a favour.

In doing so, they have also indicated that the United States has moved beyond September 11, 2001, as a political symbol. Mr Giuliani constantly reminded audiences of his adept response to the terrorist atrocities of that day to the extent that 9/11 seemed to be not a date but his slogan. He failed to appreciate that he was asking for an endorsement of the past, not offering a plan for the future. The broader theme of national security is, correctly, of huge significance in 2008 but Americans are, admirably, looking outwards, not inwards, on foreign policy. Mr Giuliani never bothered to visit Iraq or Afghanistan once while preparing his presidential quest. Mr McCain, by contrast, has been to this region more often than any other member of Congress. With the departure of Mr Giuliani (and John Edwards, the self-appointed prophet of protectionism, on the Democratic side), the demagogic aspect to this contest has been sharply diminished. As a consequence, Americans will have a better choice.