No politician in modern history has prepared to take office with so much so public expectation. And not just in America. The world is watching with bated breath.
The trouble is that big hopes can turn out to be delusions. Within days of the inauguration -- maybe even on the day itself -- the first promise will be met - a formal announcement that Guantanamo Bay is closing. Not on day one. Probably not even 100 days in. It isn't so easy. This prison camp and its inmates can't vanish in a magic puff of smoke just because Mr Obama says it should.
And will the world go instantly green when the new man in the White House waves his hand? In a vicious global downturn, safeguarding jobs at home will certainly come much higher up the list than saving the planet.
This probably makes me sound like a cynical old Brit but we've suffered a lot of broken political pledges on our side of the pond. We remember the election of Tony Blair in 1997 - and the huge hopes that came with him. He rose to power on a groundswell of optimism and left it with the whiff of scandal and a widespread sense of national disappointment. To watch him picking up your highest civil award, the Medal of Freedom, from George W. Bush in Washington the other day made many of my fellow countrymen squirm.
Mr. Blair and Mr. Bush have tarnished the so-called special relationship between our two countries. It will take hard work by Blair's beleaguered successor, Prime Minister Gordon Brown, to prove to the new President that the British government is right behind him.
And he and President-elect Obama do have ideas in common. Together they will argue for government intervention to crack the financial crisis. So stand by for grand schemes to grab the headlines. But proof is always in results. And time is never on the new man's side. Optimism can melt away with scary speed if he doesn't deliver fast. Good luck Mr President. You're going to need it.
By Ed Boyle