A gaffe, they say in politics, is when someone inadvertently blurts out the truth. Thus it was when Joe Biden, the incorrigibly loquacious senator from Delaware, held forth the other day about Barack Obama, his fellow aspirant for the 2008 Democratic presidential nomination. "Look," he declared, "you got the first mainstream African-American who is articulate and bright and clean and a nice-looking guy. I mean, that's a storybook, man."
The remark was of course profoundly politically incorrect, and profuse apologies were instantly on their way to Jesse Jackson, Alan Keyes, and Al Sharpton, all blacks who have run for the White House in recent years, and all of presumably impeccable personal hygiene and boasting impressive rhetorical skills.
But deep down, Mr Biden was spot on. Mr Obama, the 45-year-old junior senator from Illinois, is different. He is the first African-American candidate with a realistic chance of winning. And the reason, as Mr Biden so clumsily made clear, is that to the white majority of the country he hardly seems black at all.
This morning, at an open air rally in wintry Springfield, the capital of Illinois where he spent eight years as a state senator, Mr Obama formally launches his campaign. The site of the announcement is laden with symbolism. This first major black candidate of the 21st century will throw his hat into the presidential ring at the old State Capitol building, in which an earlier Illinois legislator named Abraham Lincoln cut his political teeth before himself moving on to the White House, where he issued in January 1863 the Proclamation of Emancipation freeing black slaves. This will be a patented "Only in America" moment, a testament to the country's astonishing mobility, its endless flux, and its capacity to reinvent itself.
Whether Mr Obama can follow the path of America's 16th and arguably greatest president is not clear. If he becomes the 44th, he will face challenges more subtle but in some respects as daunting as the Civil War: a country whose international reputation has never been lower, struggling to extricate itself from a disastrous foreign war, and whose global dominance is threatened by the ascent of China and India.
But the very fact that Mr Obama is setting out on the road is indeed, as Joe Biden puts it, "a storybook" - the climax of a meteoric career that has seen an untried newcomer, with just two years service in the US Senate, emerge as the most exciting politician of the day.
Three years ago, he was all but unknown. Then came the electrifying speech at the July 2004 Democratic convention, in which Mr Obama told his countrymen that, for all their divisions of party, race, class and social attitudes, they were united by the far more important fact that they were all Americans. That November, he won a landslide victory for the vacant Illinois Senate seat, and was immediately being touted as a presidential contender.
In retrospect, the only surprise is that the moment has come so soon. But in American presidential politics, opportunity is fleeting. In this election campaign of 2008 which has already started, anything can happen. Mr Obama is the flavour of the hour. In most polls, he already runs second only to Hillary Clinton. In some key primary states, he is narrowly ahead. After Springfield he travels to Iowa, whose caucuses kick off the primary season, before addressing a rally in his home town Chicago. On Monday, he is off to New Hampshire, the key primary state which greeted him like a rock star on a first visit last December.
But how long can the phenomenon last? Mr Obama's appeal is multi-layered, yet also shallow. His background is, by any standards, remarkable. The son of a Kenyan father and a white mother from Kansas, he was born in Hawaii - about as far away from Washington as it is possible to be born and still be eligible to run for president.
His parents (both now dead) separated a few years later, and his mother married an Indonesian. The family moved to Jakarta, where he was educated at Catholic and Muslim schools. He returned to Hawaii, before attending the Ivy League Columbia University, and Harvard Law School, where he was the first black, and youngest, president of the Harvard Law Review.
This family history, coupled with a gentle manner and a political message of reconciliation and healing, make Mr Obama one of a select group of blacks - Tiger Woods and Colin Powell are two others that come to mind - who transcend race. Whites do not feel threatened by them. Rather they make Americans feel good about themselves and a society in which this sort of ascent is possible. All of which, of course, only makes many blacks suspicious.
Right now African-Americans are not exactly flocking to the Barack Obama banner. And in a sense why should they? He does not share their slave ancestry, and grew up mainly among whites. In Chicago, he did work as a community organiser on the city's poor and largely minority South Side. But he has few links to the city's powerful black establishment.
The cases of Colin Powell, the first black figure to be seriously mentioned as a future president, offers fascinating similarities and differences. After much soul-searching, the former role model for blacks and whites decided not to seek the Republican presidential nomination for 1996, even though he was the one Republican with a realistic chance of defeating the incumbent Bill Clinton.
Mr Powell demurred largely because of the opposition of his wife Alma, reflecting not least her fear that he might be assassinated. Reluctantly, bowing to the inevitable, Mr Obama's wife Michelle has given her assent this time around. But she too fears the strains on family life and the loss of privacy for their two young daughters that the campaign will surely bring. As for assassination, suffice to say American politics are no stranger to violent death: look no further than the young president with whom Mr Obama is often compared, shot down in Dallas in 1963.
But there is an even more instructive footnote. In the end, of course, the Republicans chose the party grandee Bob Dole to oppose Bill Clinton. Mr Dole was soundly beaten but an election day exit poll in November 1996 suggested that had Mr Powell's name, not Mr Dole's, been on the ballot, the former would have won - not because of his appeal to blacks, who still overwhelmingly backed Clinton, but thanks to his popularity among whites. The same holds true now, for the time being at least.
A majority of blacks, say the polls, support Hillary Clinton, if only out of the warm glow inspired by the Clinton name. Nor should John Edwards, the third top-tier contender for the Democratic nomination be overlooked.
He is pushing a populist agenda, focused on America's glaring social injustices, that is bound to appeal to minority voters. Mr Obama himself counts on sidestepping the issue by making race irrelevant. As he said this week, "If we do a good in letting people know who I am and what I stand for, they'll make their judgement not on my race but based on how well they think I can lead the country."
There is a pristine, unsullied quality about the man that seems to lift him beyond the confines of the daily political fray - indeed the online magazine Slate has instituted an "Obama Messiah Watch." On Capitol Hill he stands out from his colleagues, and not merely because he is the only African-American member of the Senate. When the voice reading names for a roll-call floor vote intones "Mr Obama," a slight, almost delicate figure lopes forward. "At first glance, you take him for a page boy," one veteran of the press gallery said.
In Washington, no significant legislative achievement bears his name - though he is on the right side of the Iraq issue as the country turns ever more strongly against the war. Unlike Mrs Clinton, he opposed the Iraq invasion even before it was launched, and is on the record in Illinois to prove it.
But having not entered the Senate until January 2005, he was spared the key congressional vote of October 2002 when many Democrats, fearful of being labelled unpatriotic by the hugely popular (at the time) President Bush before the upcoming midterm elections, granted the White House authority to go to war. Some of those who did so, including Mr Edwards but not yet Mrs Clinton, have been forced to repudiate their vote. Obama does not have to.
For clues to his politics, the best place to look is Springfield, and his record in the state senate. There, he emerged as a committed liberal - but with an ability to see both sides of the argument. He is not an ideologue but a pragmatist who worked with Republicans across the aisle to fashion new campaign finance rules and a measure of healthcare reform. In extreme cases, he favours the death penalty - in a state that has now imposed a moratorium on capital punishment. In short, in the classic division of politicians into warriors and healers, Mr Obama is as emphatically the latter as President Bush is the former.
Indeed, part of his appeal is the lack of a paper trail of significant votes, as the candidate himself admits. "I am new enough on the political scene that I serve as a black screen on which people of vastly different political stripes project their own views," he writes in his best-selling - and eminently readable - political memoir The Audacity of Hope. A short Senate career is also his strength.
John Kerry's 20 years in the Senate bequeathed a paper trail of votes and a convoluted legislative style that probably cost him victory against George Bush in 2004.
Mr Obama has no such "form." There is no risk of him making statements like "I actually voted for the $87bn before I voted against it," that fatally nailed the Massachusetts senator and had him branded as as a "flip-flopper."
As for complaints that Mr Obama lacks the experience to lead America in a desperately complicated world, his response is simple and devastating. The Bush administration, with the likes of Powell, Dick Cheney and Donald Rumsfeld had perhaps the most experienced national security team in US history, he says - and look what a mess they made of things in Iraq, and what they've done for America's good name in the world. Enough said.
Instead, Mr Obama projects himself as fresh and new, a spokesman for a post-baby boom generation weary of the country's endless political wars, and of the hackneyed, over-hyped divisions between Red (Republican) and Blue (Democrat). In this vision of things, the cautious and calculating Mrs Clinton is yesterday's woman, the candidate of the status quo.
At this point, the mantle of JFK fits easily on his shoulders. In reality, a president Barack Obama would be 47 when he took office, four years older than Kennedy was on Inauguration Day 1961.
But he projects something of Camelot's glamour and excitement, and shares Kennedy's self-deprecating charm, not to mention his stirring ability as a speaker, and has an ability to attract powerful supporters.
His emerging campaign team is very strong. His fundraising ability, even with the formidable Clinton machine ranged against him, is massive. If New York is lining up behind Mrs Clinton, Chicago is going with Mr Obama and - even in Clinton-besotted Hollywood - the big donors are giving the man from Illinois a very serious look.
In the invisible but crucial "money primary," he is at least holding his own.
But now the visible contest, too, enters a new phase. As Senator Biden noted, Mr Obama is "clean". But he is not perfect. On the sin scale's trivial end, he is desperately trying to kick smoking. More seriously, queries have been raised about a 2005 land deal with Antoin Rezko, a sleazy Chicago fundraiser and fixer, which the candidate has acknowledged as a "bone-headed" mistake. If there are other, more serious skeletons in his closet, the relentless scrutiny of a presidential race will surely expose them.
The real questions, however, lie elsewhere. This talented newcomer may drip charisma from his pores but does he have substance? Back in 1984, former vice-president Walter Mondale, the Democratic establishment's candidate for the White House that year, famously asked his upstart challenger Gary Hart - also long on theory but short on specifics - "Where's the beef?" In Obama's case, too, it is legitimate to wonder what, if anything, lies between the two alluring parts of the hamburger bun.
Second, is there steel to go with the charm? This election is the most open in decades, the first since 1928 in which neither a sitting president or vice-president is running. It will be a ferocious battle. Some Republicans (or was it a rival Democratic camp?) have been falsely putting it about that the Islamic school he attended in Jakarta was a hothouse of Islamic extremism. In case you missed the point, the more childish conservative commentators roll their lips around his full name - Barack Hussein Obama, just one letter short of being an exact combination of America's two greatest recent enemies.
Finally, the third question, the most important of all: can he do it? The very title of his book sets the frame for his campaign.
There is audacity, to be sure. Little could be bolder and more presumptuous than for an untested 45-year- old - whatever the colour of his skin - to put himself forward as saviour of the world's most powerful country, trapped in an unwinnable war, its global reputation at a nadir, when even history seems to be turning against it. The next president will be inheriting a whirlwind.
But Mr Obama also epitomises hope. That commodity is fragile, and needs much nourishing. Who will be your greatest enemy, he has been asked. His answer is one word: "cynicism."
But for the moment Barack Obama, more than any other candidate ,offers hope. That will be his message in Springfield, Illinois, today, as the last piece in his campaign falls into place.
Let battle commence.
The first billion-dollar election
The 2008 US presidential election is shaping up as the first billion dollar campaign for the White House, in which the system of federally-funded spending limits will effectively no longer apply.
The pattern was set in 2004, when both George W. Bush and his Democratic challenger John Kerry opted out of the system, funded by voluntary contributions by taxpayers, which might have provided $150m (£76m).
Both Hillary Clinton and Barack Obama on the Democratic side have indicated they will take the private route, while John McCain on the Republican side is set to do the same.
Ms Clinton is by far the best financed candidate so far. Her aim is to create a sense of inevitability about her campaign - and the best financed candidate does indeed usually win.
Many smaller states feature low cost "retail" politics, where a candidate campaigns in person. In big states however, hugely expensive TV advertising spots are the only way to reach voters.
The $75m or so that is available under the old system would simply not be enough.
Long walk to freedom: milestones in the fight for African-American civil rights
Thurgood Marshall, a lawyer for the National Association for the Advancement of Colored People, successfully persuades the Supreme Court that segregation in schools is unlawful.
Rosa Parks, an Alabama seamstress and activist, refuses to give up her seat in the "coloured" section of a bus to a white man and is arrested. Her act prompts a national escalation in civil disobedience.
Eisenhower sends troops to escort nine black pupils from Little Rock, Arkansas to a previously white-only school.
Federal troops are sent to protect James Meredith, the first black student at the University of Mississippi, after riots break out.
To a crowd of 200,000 on Capitol Hill, civil rights leader Martin Luther King Jnr delivers his "I have a dream" speech. Broadcast worldwide, it propels the civil rights movement into the political mainstream.
After the Ku Klux Klan murder four black girls in a bomb attack on a church, President Lyndon Johnson signs the Civil Rights Act.
Controversial black leader Malcolm X is shot 16 times as he delivers a speech in New York. Three men are arrested and convicted, yet conspiracy theories continue to dog the investigation of his murder.
Martin Luther King is assassinated outside his hotel room by James Earl Ray, an escaped convict. Despite promoting peaceful protest while alive, King's death sparks riots in more than 60 cities.
Shirley Chisholm, the first black woman to enter Congress, becomes the first African-American to make a bid for presidential nomination. Chisholm later said she ran for the office "to demonstrate the sheer will and refusal to accept the status quo".
Reverend Jesse Jackson, a veteran civil rights leader and Baptist minister continues to challenge race prejudice within American politics by making bids for the Democratic presidential nomination. Despite winning more than three million votes in 1984, he comes in third place.
Colin Powell, a four-star general, becomes the first African-American to be appointed Joint Chief of Staff, the highest position in the US Army. Powell later becomes the first black Secretary of State under George W Bush.
The worst race rioting in a decade kills 53 and tears the cosmopolitan city of Los Angeles apart, after a mainly white jury acquits four police officers of assaulting Rodney King, a black motorist. The riots provoke much soul searching in America over whether racial prejudice is really dead.
Republicans break another political race barrier after Condoleezza Rice, a former professor at Stanford University and a long-term friend of the Bush family, becomes the first African-American woman to be appointed to the post of Secretary of State.
Jerome TaylorReuse content