The 21st century began late for America, on 11 September 2001. Before that day, the US still defined its role in the world with reference to ideological triumph in the Cold War that had dominated the century just passed. It was the planet's only superpower and saw itself as a popular champion of global democracy. Few expected the nation to come under attack, least of all the man who had been installed in the White House a year earlier. In 2000, George W Bush was uninterested in foreign affairs. He was ill-equipped to be the first US President of the new millennium.
Mr Bush found moral purpose in response to terrorism, modelling his response on Cold War rhetoric as a battle between good and evil. But he will leave office unable to claim victory. Meanwhile, foreign entanglements led him to neglect economic and social policy. He inherited a budget surplus of $236bn, which was spent on defence and tax cuts for the rich, leaving a deficit of nearly $500bn as the country enters a recession. It is a sad legacy after two terms in office.
So it is no surprise that opinion polls show voters ready to punish the Republican party. Even if John McCain pulls off a surprise victory, beating Barack Obama to the White House, he will have to govern in deference to a Democratic Congress.
For the Senator John McCain of 2007, that would not be a problem. He had a reputation for pragmatic bipartisanship and principled opposition to the excesses of the Bush administration. He sponsored campaign finance reform; he decried state-sanctioned torture; he backed measures to halt climate change; he opposed unaffordable tax cuts. At the start of the campaign, Democrats feared Mr McCain would woo voters in the centre ground, while conservatives feared he would betray their agenda of moral activism against abortion, gun control and gay marriage.
Neither fear was justified. The John McCain of 2008 has abandoned the centre. There have been rightward shifts on climate change and tax, but the change is mostly a matter of tone. Mr McCain has tried to portray Barack Obama as an unpatriotic socialist. But most extraordinary was the selection of Sarah Palin as a running mate. That was an attempt to position Mr McCain as a tribune in the Culture War between secular liberals and religious conservatives that has paralysed US politics for generations. Sarah Palin represents a strand in Republican thinking that sees the party's mission as perpetual insurgency against an un-American conspiracy run by a cosmopolitan Washington elite.
But the job of a Vice-President is to stand in should the Commander-in-Chief be unable to serve. Ms Palin has disqualified herself from that responsibility by showing a woeful grasp of policy. By promoting her, Mr McCain brought his judgment into question. He also made himself a candidate of old divisions, against Mr Obama's promise of unity and change.
The long campaign has tested the characters of both candidates, especially when global economic crisis forced them to abandon prepared scripts and perform by instinct. Barack Obama won that contest easily. His policy prescriptions, essentially a redistributive tax agenda, were fairer and more responsible than Mr McCain's panicky pledge of tax-cuts. In style, Mr McCain's reaction was slow and choleric, while Mr Obama's was steely and swift. The Democratic candidate thus refuted what had been the strongest argument against his candidacy - that he lacked leadership stature.
That makes for a marked contrast with the diminished and discredited White House incumbent. George W Bush's reign is now recognised, even by non-partisan American commentators, as a colossal failure. He spent two terms misapplying the old foreign policy doctrines of the Cold War to a new security threat and exploiting the old enmities of the Culture Wars to shore up his power.
Mr Bush failed the test that history set him: to lead America into the new millennium. America is still waiting for a 21st-century President. It has one ready to serve in Barack Obama.