A black President in the White House. It shouldn't seem extraordinary, but that ignores decades of history and prejudice.

President-elect Barack Obama: a day many Black Americans thought they would never see.

Earlier this year at the Oscars ceremony in Hollywood, host Jon Stewart joked that "when you normally see a black man or a woman President, an asteroid is about to hit the Statue of Liberty."

Electing either Barack Obama or Hillary Clinton would have been a seismic event, but Obama's victory will reverberate around the world.

The new President, his elegant and eloquent First Lady Michelle, and two pretty little black girls called Malia and Sasha. America's First Family.

Now imagine if Hillary had been elected and she and Bill were moving back into their old home. It would look as if we were turning back the clock, not fast-forwarding into a brave new world.

That is not to denigrate how close we came to a first woman President. Women have been victims of discrimination in the workplace.

But it cannot compare to the way generations of African Americans were treated until relatively recently.

Just look at images of lynchings, cross burning, segregated schooling and restaurants, and police dogs and water cannon being used against protesters demanding equal rights.

Many of the people who spent years being treated as second-class citizens will have voted for Barack Obama.

Many believed they would never have the chance to vote for a black President, and even fewer would have believed the country would have elected him.

Black America 'Pull Your Pants Up'
A few days ago I met a man who told me how his father had turned up to vote at a polling station in Mississippi soon after the Second World War.

The white official at the polling station turned him away. "You know you can't vote." "Why can't I vote when five of my sons are fighting for their country in the military?" he asked. The official relented so long as the man didn't tell anyone.

In the law offices of Virginia State Senator Henry Marsh, a small framed poster hangs on the wall. "Hands that picked cotton can now pick elected officials".

It's a reminder of how recently American suffrage became universal. Senator Marsh once attended a segregated school. Now he's chairman of the committee that picks the state's judges.

When you ask him whether he marvels at how far America has come, or whether he wonders why it has taken so long, he pauses. "Both" he replies.

This is not Barack Obama's achievement. It is the achievement of generations of people, thousands of people who believed in America and who sacrificed.

Henry Marsh, Virginia State Senator
"It says the promise of America isn't an empty promise. In some cases it can be a reality. So it's an exciting time to be alive and well and American, especially an African American who went through what some of us went through."

You can go further back in American history to realise how much the country has changed.

Senator Marsh lives in Richmond, Virginia, which was once the capital of the Other America - the short-lived Confederate States of America, which fought against Abraham Lincoln's attempt to end slavery.

Statues of Civil War heroes like Jefferson Davis and Robert E. Lee still dominate the city. But now there is a new monument celebrating heroes of Virginia's history. A Civil Rights monument depicts ordinary people who fought to be treated equally. An engraved quote reads: "It seemed like reaching for the moon."

How would they sum up Barack Obama's achievement in reaching the White House? What he achieves in office will determine his legacy, and whether he joins revered names such as Martin Luther King.

Obama may have advanced the cause of black people, or at least inspired others to follow in his path. But he did not pander to black voters during the election campaign, and he spoke out against a White America and a Black America.

Instead he will have to deliver on his promise of a truly United States of America.