He added: "I promise to make this a smooth transition. You are about to go on one of the great journeys of life. Congratulations, and go enjoy yourself."
The election was in many respects a referendum on the two-term president, whose popularity has plunged to the lowest levels since the 1930s, because of his administration's handling of the economy, Hurricane Katrina, and the wars in Iraq and Afghanistan. Bush has not been seen with McCain since May, and the president has made no public appearances since late last week.
McCain's top strategist acknowledged the team's difficulties as the candidate returned to Arizona from his final campaign stop in New Mexico.
"I think we did our absolute best in this campaign in really difficult circumstances. We had a -- we had some tough cards to play all the way through and we hung in there all the way," senior adviser Steve Schmidt told reporters.
He added: "I don't think there's another Republican the party could have nominated that could have made this a competitive race the way that John McCain did. . . . The president's approval numbers, you know, were not helpful in the race but the party as a whole is unpopular with the American people, and that was a big albatross."
During a sometimes chaotic race, McCain promised voters that he would reform a broken and corrupted Washington and bring change that he said the American people demand. But his economic and national security proposals largely echoed Bush's policies, a charge that Obama made repeatedly.
Republicans watched yesterday as the electoral map turned blue in places where they have labored for a decade to cultivate a permanent, conservative voter base that would ensure presidential victories.
The party -- now clearly a minority one -- is left wondering whether the Democratic rout is the result of a coincidental marriage of a powerful personality and a terrible political and economic environment or if it signals a deeper change in voter patterns and beliefs that will make it difficult for them to recapture the White House for years.
"This election, particularly when combined with the '06 election, means the GOP is in serious trouble," said Peter Wehner, a former Bush White House aide. "To deny that would be to deny reality."
Wehner said the party can take some comfort in "the fact that I suspect the data will show that America remains, on the issues, a center-right nation. . . . It means the core political philosophy that defines the GOP is not out of sync with the country."
In a sign that Obama's race did not hold him back, he won as large a share of the white vote as any Democrat in the past two decades, although he still fell short of a majority. Preliminary exit polls showed him winning among 43 percent of white voters, while Sen. John F. Kerry won 41 percent in 2004 and Vice President Al Gore won 42 percent in 2000.
McCain styled himself as a maverick but ran a largely traditional Republican campaign that eroded his brand among independents, the majority of whom voted for Obama yesterday. Obama won 60 percent of self-described moderates, who had once formed the core of McCain's support.
Obama appeared to have made huge gains among Hispanic voters, earning about two-thirds of their support, according to exit polls. He also captured 95 percent of black voters. Obama also won a majority of women and took the support of 49 percent of men.
McCain appeared to have performed more poorly than his GOP predecessors, especially among young people. He earned about 30 percent of voters aged 18 to 29; in 2004, Bush captured 45 percent of that group.