With a gracious nod to Barack Obama, John McCain acknowledged defeat and urged his supporters to move beyond partisan differences to put country first — an echo of his campaign theme.

“I wish godspeed to the man who was my former opponent and will be my president,” McCain said as he conceded the presidency he has sought for a decade.

The four-term Arizona senator added: “These are difficult times for our country. And I pledge to him tonight to do all in my power to help him lead us through the many challenges we face.”

Flanked by his wife Cindy and his running mate Sarah Palin, McCain stepped before supporters at the Biltmore Hotel on a balmy Tuesday evening shortly after telephoning Obama to offer his congratulations and concede the race. He implored his backers to fall in line behind Obama and put aside partisan bickering. And, he pushed back on a smattering of boos and shouts of “No-Bama! and “Reverend Wright,” a reference to Obama’s incendiary former pastor.

“Whatever our differences, we are fellow Americans,” McCain said. “No association has ever meant more to me than that.”

After an intensely negative campaign, McCain went to lengths to take the high road in his concession speech and acknowledged the historic nature of Obama’s barrier-breaking accomplishment.

“His success alone commands my respect for his ability and perseverance,” McCain said, adding that he “deeply admired” Obama for inspiring the hopes of people “who had once wrongly believed that they had little at stake or little influence” in electing a president.

“This is an historic election, and I recognize the special significance it has for African-Americans and for the special pride that must be theirs tonight,” McCain said, adding that the U.S. had moved “a world away” from its racist past by electing the nation’s first black president.

He allowed that disappointment was natural but said that starting Wednesday “we must move beyond it and work together to get our country moving again.”

“We fought as hard as we could. And though we feel short, the failure is mine, not yours,” McCain said.

Also, he praised Palin as “one of the best campaigners I have ever seen, and an impressive new voice in our party for reform.”

By McCain’s own admission, it was a disappointing end to a quest he began sketching 10 years ago before his first run for president in 2000. He was vanquished that time by George W. Bush in the Republican primaries, but won the affection and respect of many voters who admired his independent streak and dedication to honor and service as a former Naval officer and prisoner of war in Vietnam.

McCain entered this campaign as the perceived GOP front-runner but saw his effort nearly implode in July 2007 amid staff tension and vast overspending. He was able to rebuild his candidacy by grinding out key wins in the New Hampshire, South Carolina and Florida primaries.

He faced long odds from the start of the general election, running as the GOP successor to President Bush who had become deeply unpopular amid a troubled economy and two wars. But then McCain put the little-known Alaska governor on the GOP ticket and polling shortly after the Republican convention found McCain pulling slightly ahead of Obama.

Then the global financial crisis hit, and McCain’s hopes were dashed. Voters usually punish the party in power when the economy tanks, and this year was no different.

In the campaign’s final days, the GOP nominee maintained a grueling campaign schedule while being well aware of the odds against him. He stumped across Colorado and New Mexico after a 24-hour cross country journey across battleground states that ended after midnight Tuesday.

But McCain also acknowledged he’d made mistakes in his campaign and that he had let his supporters down.

“I don’t know what more we could have done to try to win this election. I’ll leave that to others to determine,” he said.