There are rare moments in history when the ordinary get a chance to be extraordinary, to shine, when a man for the moment emerges like a butterfly from its drab cocoon.
When Missouri farm boy Harry Truman was forced to step into the shoes of Franklin D Roosevelt in 1945 America held its breath. With "almost complete unanimity," Time wrote, his friends "agreed last week that he would not be a great President". The then Speaker of the Senate, Sam Rayburn, saw him as "right on all the big things and wrong on most of the little".
Washington enjoyed the tales of his faux pas and lack of sophistication.
But Truman surprised them. Behind the earthiness and simplicity of his language was a clear and coherent view of the world challenges faced by the US and an ability, at least in foreign policy, to see it through. And history's verdict on the unlikely President is more than kindly.
Now, eight months into his lacklustre term, George W. Bush has been propelled onto the stage of history to show qualities of leadership he never dreamt he had.
A traumatised country needs someone to articulate its collective pain and anger, to avenge its dead, and then to express its confidence in the future. It needs someone to take tough decisions. It needs a real President, not just someone who happens temporarily to inhabit 1600 Pennsylvania Avenue.
Much hangs on whether he, like Truman, can show that in his own words he has been sorely "misunderestimated". Or, now that it really matters, do we now find out the emperor really has no clothes? It is a challenge of daunting proportions and requires a substantial change of style from a politician who has made laid-back and downbeat presentation into an art form.
His words must not just strike the right tone but must resonate with the American people in the way that Bill Clinton caught the mood after the Oklahoma bomb and Tony Blair after the death of Diana.
It is a task made all the more difficult by the style of politics these days - idealism sounds phoney, and Bush does not do it well.
FDR had spoken after Pearl Harbour of a day that "will live in infamy", words that are still remembered. And, as Kenneth Walsh of US News and World Report recalls: "When Ronald Reagan was shot in 1981, he told his wife, 'Honey, I forgot to duck', a line that heartened Americans about their president's calm under pressure". But although Bush said the right things his words on Tuesday sounded hesitant and were utterly unmemorable apart from the faux pax-folksy reference to catching the "folks" who were responsible for the attacks. "He went for Texas plain talk, rhetoric as flat as the prairie and as blunt as a Clint Eastwood soliloquy," Howard Fineman of Newsweek wrote.
On Thursday he was filmed on TV talking on the phone intently to New York's Governor, but his vigorous promises that he would do all he could for the city had the ring of a man acting for the cameras.
Nor was Bush's profile helped by the mishandling by his usually skilful spin doctors of the reasons for his circuitous return to Washington on Tuesday via Louisiana and Nebraska. Only after political criticism of his absence from the helm at the White House had begun to gather momentum did they leak the perfectly acceptable reason - that they had good reason to believe Air Force One was still a target.
"George Walker Bush has never wanted to be a hero, only president. Now he has to be the former to succeed as the latter," Fineman says, arguing that he has to lift his game substantially.
Bush has always given the impression that unlike his ideologically driven predecessors, Clinton and Reagan, he was more interested in the job itself, and keeping it, than in what he could do with it, not least because he felt his father had been unjustly deprived of a second term. He prides himself on a management style more akin to a CEO than a politician, but a politician's knack for the telling phrase is what is called for now, particularly from a man many Democrats believe stole the election, courtesy of the Supreme Court.
He has, however, a huge well of goodwill to draw on now. The attacks have led to a national coming together, a mood of unity that has seen politicians falling over each other to rally to the flag. On Thursday night both houses of Congress voted through with unprecedented speed a $40 billion extension to the budget.
Instinctively a man of the right, Bush's repackaging of the Republicans as "compassionate conservatives" made the party re-electable, but also created ambiguities about what he would do when elected, ambiguities with which the unintellectual President had no problem.
Once elected, however, Bush set about building a competent team more in the hard-right image of his Vice-President, Dick Cheney, though leavened by a few pragmatists like Secretary of State, Colin Powell.
Bush pledged to change the confrontational language of Washington, to rule in a bipartisan way. But Democrats found that there was little willingness in the White House to meet them halfway and they fought him bitterly on his whole programme, particularly the deeply regressive tax cut package. With the defection in June of centrist Republican James Jeffords to the ranks of independents, they won back control of the Senate and the battles became all the more fierce.
Ironically it has taken external force majeure to bring about precisely the bipartisan spirit that Bush had sought, a willingness by Democrats to do things his way. How long that lasts on the nitty gritty of domestic appropriations bills is difficult to predict - indeed it depends largely on Bush's ability to capture the mood of the public - but on defence the President already appears to be winning the argument.
Republicans are already speaking more confidently of getting the controversial missile defence budget through. "I believe the American people are going to be roused out of an unwarranted sense of security to reflect on their vulnerability and the desire of some people around the world to take advantage of it," says Frank Gaffney, head of the Centre for Security Policy.
Although the foreign policy agenda, like the domestic, appears to date to have been driven by the right, Colin Powell's influence told significantly during the crisis over the Chinese downing of a US surveillance plane. After an initial rhetorical blast at the Chinese, Bush showed a willingness to lower the tone of exchanges to de-escalate the crisis.
That experience and Bush's desire to consolidate a global alliance against terrorism, the allies will hope, may yet temper and delay the urge to retaliate massively that is being fanned even by Democrats. Although he was the first in the Administration to declare that the US would respond "as if it is a war", Powell has also been anxious to emphasise the need for cool heads and the importance of understanding that there was no easy way to win the struggle. "Let's not think that one single counter-attack will rid the world of terrorism of the kind we saw yesterday," he said on NBC's Today programme.
"This is going to take a multifaceted attack of many dimensions - diplomatic, military, intelligence and law enforcement. All sorts of things have to be done to bring this scourge under control." But Bush's notion of an alliance is a bit like his approach to bipartisanship. As the Russians have discovered on missile defence and the Europeans on Kyoto, discussion consists in telling partners what he intends to do. And then setting about doing it.
On the new global threat from terrorism, he explained inimitably to Iowa students during the election campaign: "When I was coming up it was a dangerous world, and you knew exactly who they were. It was Us versus Them and it was clear who 'them' was. Today we are not so sure who the 'they' are, but we know they're there." But he has added a new dimension to US policy this week with his insistence that those harbouring terrorists will be treated the same way as the terrorists.
Yet if the attacks have proved anything about the new strategic realities, it is that the attachment of the conservatives in the Bush Administration to military solutions to such problems is inadequate. The US no longer enjoys the isolation that allowed it disdain what Europeans call soft security. Globalisation has brought terror to US shores but also reinforced to a point unparalleled in history the interconnectedness of US interests with others, as Bush has glimpsed in his dealings with China. If he wants to stake his claim to an honoured place in history, it is a lesson he would do well to learn.