WASHINGTON » Conceding Hillary Clinton’s staggering defeat, President Barack Obama urged the nation today to join him in rooting for President-elect Donald Trump’s success. He said he was heartened by Trump’s election night call for unity and hoped it wouldn’t fade.

Obama, in a post-election ritual meant to signal the peaceful transition of power, vowed to do all he could to ensure Trump would be well-positioned to run the country. He said he’d congratulated Trump by phone and invited him to sit down together at the White House.

“We all want what’s best for this country,” Obama said.

Standing in the Rose Garden, with Vice President Joe Biden at his side, Obama spoke to more than a hundred of his White House staffers, who stood silently, dazed, some crying, before breaking out into a prolonged round of applause that continued long after Obama returned to the Oval Office.

Obama’s conciliatory reaction to the election marked an attempt to buck up Democrats reeling with disappointment, shock and uncertainty about the future. He said he’d told his staff to “keep their heads up” and be proud of the “remarkable work” they’d done.

Left unsaid was that Trump has vowed to aggressively undo most of what Obama has accomplished, leaving Obama’s supporters fearful that the last eight years may have been in vain.

But the president, standing in front of the Oval Office, downplayed the notion that Trump’s presidency would mean an about-face for the nation. He said the U.S. has a tendency to “zig and zag” rather than move in a straight line, and he added, “That’s OK.”

“That’s the way politics works sometimes,” Obama said. “We try really hard to persuade people that we’re right and then people vote. And then if we lose, we learn from our mistakes, we do some reflection, we lick our wounds, we brush ourselves off, we get back in the arena, we go at it. We try even harder the next time.”

Obama spoke just moments after Hillary Clinton formally conceded to Trump with a similar, though more emotional, appeal to give Trump a chance to succeed as president. The remarks were striking after a campaign in which the Democrats declared Trump was unfit to serve and told voters the future of democracy was riding on their choice.

The White House said Obama and Trump are expected to meet Thursday to discuss the handover of power and ongoing planning for the transition. Obama called the Republican in the early hours of the morning today to congratulate him on his stunning victory, which marked a forceful rebuke by voters to Obama’s eight years in office.

For Obama, turning over the White House to Trump is a devastating blow to his legacy and to his hopes for leaving a lasting imprint on the nation’s policies. Trump has vowed to rip up much of what Obama accomplished, including his signature health care law, the Iran nuclear deal and a painstakingly negotiated trade deal with Asia.

With Republican control of both chambers of Congress, Trump will be well positioned to make good on that promises.

Obama called Clinton after it became clear she’d lost the race. In his Rose Garden remarks, he paid tribute to her historic candidacy and said, “I could not be prouder of her.”

It was unclear how substantive Obama’s call was with Trump, or how long it lasted, although the White House noted that Obama placed the call from his residence in the White House, rather than from the West Wing.

Trump’s campaign manager, Kellyanne Conway, described it as a “warm conversation” and a “gracious exchange.” She said Trump had missed the president’s original call as Trump was speaking to supporters in New York, then called him back after leaving the stage.

Like Clinton and other Democrats, Obama didn’t appear to see Trump’s victory coming. As he campaigned vigorously for Clinton in the race’s final days, Obama said he was confident that if Americans showed up to vote, they’d choose against electing the billionaire former reality TV star with no formal government experience.

He had also warned supporters in apocalyptic terms that “the fate of the republic” rested on Clinton defeating Trump on Election Day.