Washington on the eve of Barack Obama's inauguration resembles Rio de Janeiro during a riotous carnival held under martial law. Police patrol every corner, traffic obstacles cut across the avenues, cars and bicycles are stocked in parks on the edge of the city centre.
Inside the ring of steel, however, are all the inaugural trappings that huckstering genius of America's commercial civilization can provide. As one conservative grinch, Ramesh Ponnuru, observed in Time magazine: "Also available are Obama coasters, lava lamps, jigsaw puzzles, mugs, skateboards, toy trains, CDs, DVDs and, of course, commemorative dinner plates. Ben & Jerry's is introducing a Yes Pecan flavor in honor of Obama's campaign slogan, and Marvel Comics is running a special Inaugural issue of Spider-Man. Pepsi has created the Pepsi Optimism Project with a red, white and blue logo almost identical to Obama's sunrise button. And Obama's face now graces subway tickets sold in the nation's capital."
All this reflects a national, rather than partisan, mood. The Obama inauguration seems to unite almost all Americans in a mood of patriotic self-renewal even as they face a grave economic crisis.
The mere fact of America's first black president explains some of this. Blacks are naturally pleased that this final barrier to their advancement has been crossed. Most whites have long wanted to vote for a black president - Colin Powell would have won handily 12 years ago if he had thrown his helmet into the ring. Now that one is about to take office, all but a handful of white racist "bitter-enders" are proud. No one feels remotely threatened.
All this indicates that Mr. Obama's election is not a revolution. Revolutions never cause universal rejoicing. It is rather the constitutional culmination of three revolutions: the liberty proclaimed in 1776, the equality won by the Civil War and the civil-rights struggle begun at Montgomery and Little Rock. Mr. Obama symbolizes the achievement of a post-racial American democracy to which all these pointed.
But Mr. Obama is a man as well as a symbol. His personal qualities appeal at least as powerfully as his race to all sorts of Americans.
His Ivy League law background excites educated voters. His stance of "ironic cool" in interviews wows the young. His gentlemanly manners and lithe elegance - he is closer in style to Fred Astaire than to any U.S. politician - charm suburban whites generally and white women in particular.
Finally, his political career has recruited or neutralized a highly disparate coalition of activist groups. His early opposition to the Iraq war thrilled left-wing radicals. His turning a judicious blind eye to the workings of the corrupt Chicago Democratic machine impressed party regulars. His lockstep support for liberal measures in both the Illinois Senate and U.S. Senate reassured reformers. His courteous debating tactics pacified conservative critics.
In other words, Mr. Obama is a charming sphinx-like enigma on whom the rest of us can impose our hopes for change.
During the campaign, he was able to smother these contradictions in speeches of distracting eloquence. But to govern means to choose, and to choose means to disappoint. His early choices - Hillary Clinton for secretary of state, Larry Summers as White House economic adviser - have disappointed his early radical supporters by virtue of their cautious moderation. How will he govern after today, and whom will he disappoint?
Most recent analyses of Mr. Obama's politics might as well be published by Marvel Comics as part of the Pepsi Optimism Project. They wish away the contradictions. Resolving the contradictions, however, boils down to choosing between the politics of Mr. Obama's record until the 2008 campaign and the politics of Mr. Obama's 2008 campaign.
Until 2008, Mr. Obama reliably backed his party's left-liberal policies and its allies in labour unions and ethnic interest groups. He depicts himself in his memoirs as committed to policies of black empowerment. Yet, in 2008, he campaigned as a new post-racial and post-partisan healer.
Today, he will take the oath of office before an official Washington dominated by liberal Democrats eager to reverse the conservative trends of the Reagan-Bush era. There will be enormous pressure on him to stick with his past record, go along with the congressional Democrats and reward his party's allies with policies such as entrenching racial preferences and favouring union recruitment.
Such policies would push Mr. Obama toward a strategy of consolidating the party base rather than widening his new coalition. That would be risky any time, but especially so during an economic recession.
On the other side of the scale is the likely influence on Mr. Obama of his election victory. He won as a post-racial post-partisan. His rhetoric swayed many previously apathetic voters. Might it not have influenced Mr. Obama himself?
He won near-Soviet majorities from black voters, but also a larger share of the white vote than the past two Democratic (and white) contenders. Keeping such voters in 2012 will be essential to the survival of Mr. Obama's post-racial/post-partisan coalition. That strategy, in turn, points to practical ways of achieving equality - curbing teachers' unions to improve schools; asking black kids to embrace "white middle class" standards; cutting payroll taxes that destroy blue-collar jobs - that would alienate many Democrats.
Mr. Obama sees himself as the heir to Abraham Lincoln (who also represented Illinois). He admires Lincoln's second inaugural, in which he called for "charity for all" and "malice toward none" near the close of a bloody civil war.
To match that level of greatness, Mr. Obama will have to find simple but ringing phrases, biblical in tone, to summon the united America that is emerging in order to restore the dynamic and prosperous America that is being lost. Or he may simply go along with his party and prove to be what Bismarck called Napoleon III, namely "a sphinx without a riddle."
John O'Sullivan is senior fellow at the Hudson Institute.