Who is the smart bet for first black president of the United States? Less than a decade ago, Colin Powell was the man - and to this day, some believe the general might have beaten Bill Clinton back in 1996. Today the mantle has fallen on a somewhat more improbable figure - Barack Obama.
American political junkies love nothing better than to plot White House match-ups down the line, and nothing brings out the habit like convention season, when vast amounts of hot air are expended, but nothing much happens. The match-up of the year, in this case George Bush and John Kerry, has long since been talked to death.
The public topic here in Boston is whether Mr Kerry can galvanise swing voters and win back the White House. The unofficial one is more fun: what happens in 2008 if he doesn't, or in 2012 if he does? A Kerry win this year would obviously make his running mate, John Edwards, heir apparent. A loss would put Hillary Clinton squarely in the frame. But 2016, and Barack Obama - Barack who? The mystery only deepens when you learn the person in question is but a state senator in Illinois, who is a Democratic candidate, and it must be said, clear favourite in the contest for the open US Senate seat in the state in November's election.
Yet this 42-year-old politician, all but unknown nine months ago and who has not yet set serious foot in Washington DC, has already been glowingly profiled in New Yorker magazine, and scrutinised by the most distinguished political columnists in the land. Last weekend, Mr Obama was the headline guest on the country's top-rated Sunday talk show, NBC's Meet the Press. Tonight he receives a rookie's crowning distinction - picked to deliver the keynote speech that will cap the convention's second day.
One reason for this astonishing showcasing is simple: it can only boost the Democrats' chances of capturing the US Senate seat held by the retiring Republican incumbent, Peter Fitzgerald. Given the host of tricky seats the party must defend, a gain in Illinois is vital if the Democrats hope to regain control of the Senate they lost two years ago. If a little primetime exposure helps the cause, then so much the better.
Also Mr Obama's background - exotic even by US melting pot standards - dovetails perfectly with the party's aim to appeal across class and race.
His father was Kenyan, his mother came from Kansas. The couple met in Hawaii, and sealed a union appreciated neither in Africa nor on the Great Plains. She later married again, to an Indonesian oil executive, and the new family moved to Jakarta. Then life's winding road led Mr Obama back to the US - to California, Chicago and Harvard law school, where he was the first black president of the Law Review. But political calculation, and even that perfect CV are only the part of it.
The keynote speaker is someone whom party elders reckon will be a big part of the Democratic future. Traditionally the speech, setting the party in the spirit of the times, is delivered by an especially bright rising star. In 1988 for instance, the keynoter was a young Arkansas governor named Bill Clinton - even though his memorably turgid speech was the biggest bomb of his otherwise illustrious oratorical career.
Mr Obama, like the former president, has magnetism. He is slender, seemingly ever smiling, conveying the awareness that great honour has been heaped upon him, but serving notice that he will keep a very level head amid all the fuss.
But he is considerably more than a pretty face.
He is on the left of the party, not least on Iraq. Back in summer 2002, he declared that Saddam Hussein's decrepit regime was no threat to anyone, its weapons' capability much exaggerated, and that the US had no business launching an invasion. John Kerry, among others, thought otherwise, but events have proved Mr Obama right.
More important, he has a rare knack of making liberal positions sound reasonable. He can advocate a larger role for government in mapping national economic policy, without coming across as a tax-and-spend liberal. He also has long espoused what is now Democratic orthodoxy, that the party should keep its nerve and carry the battle of ideas to Republicans.
So the Barack boom continues. He has been helped by the shambolic Republican efforts to find a candidate to oppose him in Illinois. (Two have dropped out amid scandal, and a putative third, the former coach of the Chicago Bears NFL football team, decided that the venture wasn't worth the trouble.) Ahead by 20 points in the polls, he seems destined to win. And then who knows? By 2012, he will have been US senator for eight years (just like the John Kennedy in 1960) and by 2016, he will be a very presidential 54 years of age. Of such stuff are convention scenarios spun.