President-elect Barack Obama can "count on complete cooperation" after his "impressive victory" as he prepares to take over at the White House, President George Bush said today.
Mr Bush said Mr Obama's "journey represents a triumph of the American story".
"The long campaign is now ended and we move forward as one nation," Mr Bush said.
"It will be a stirring sight to watch President Obama, his wife Michelle, and their beautiful girls step through the doors of the White House," Mr Bush said.
"I know millions of Americans will be overcome with pride at this inspiring moment that so many have awaited so long.
"I know Senator Obama's beloved mother and grandparents would have been thrilled to watch the child they raised ascend the steps of the Capitol - and take his oath to uphold the Constitution of the greatest nation on the face of the earth."
The president said he had invited the Obamas to visit him in the White House "as soon as possible".
"No matter how they cast their ballots, all Americans can be proud of the history that was made yesterday," Mr Bush said.
"Across the country, citizens voted in large numbers.
"They showed a watching world the vitality of America's democracy, and the strides we have made towards a more perfect union.
"They chose a president whose journey represents a triumph of the American story - a testament to hard work, optimism, and faith in the enduring promise of our nation.
"Many of our citizens thought they would never live to see that day.
"This moment is especially uplifting for a generation of Americans who witnessed the struggle for civil rights with their own eyes - and four decades later see the dream fulfilled."
He added: "A long campaign has now ended, and we move forward as one nation.
"We're embarking on a period of change in Washington, yet there are some things that will not change.
"The United States government will stay vigilant in meeting its most important responsibility - protecting the American people.
"And the world can be certain this commitment will remain steadfast under our next commander-in-chief."
Mr Bush added that he also congratulated Mr Obama's former rival John McCain on "a determined campaign".
"The American people will always be grateful for the lifetime of service John McCain has devoted to this nation," he said.
"And I know he'll continue to make tremendous contributions to our country."