Washington (CNN) An emphatically upbeat President Barack Obama promised Wednesday to work toward a "smooth transition" of power to the man he's spent the last year denigrating, insisting that despite his differences with President-elect Donald Trump he would uphold the central tenet of American democracy.

Speaking in the Rose Garden as some of his aides sobbed, Obama made a deliberate effort to counter Democrats' crushing sense of doom at the prospect of four years of President Trump.

"It is no secret that the President-elect and I have some pretty significant differences," Obama said with Vice President Joe Biden at his side. "We are now all rooting for his success in uniting and leading the country."

It was a markedly different tone from Monday, when Obama was aggressively campaigning for Hillary Clinton in a final, frantic bid to get her elected. He has said on the campaign trail that Trump is unprepared and " unfit " to be president, and warned that electing him would result in eight years of progress being washed away.

On Wednesday, Obama didn't mention the long roster of his policies that Trump has vowed to reverse, or the proposals the Republican has suggested that Obama deemed dangerous and un-American.

Nor did he reprise any of his attacks on Trump's character, which he said during the campaign were un-American.

Instead, Obama sought to cast the election results as a natural swerve in the nation's political trajectory.

"The path that this country has taken has never been a straight line," Obama said. "We zig and zag and sometimes we move in ways that some people think is forward and others think is moving back, and that's OK."

"That's the way politics works sometimes," he 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 said he wanted to emulate his predecessor, a Republican, in smoothing the transfer of power.

"The presidency and the vice presidency is bigger than any of us," Obama said.

Over a hundred White House staff members -- including aides who have worked for Obama since his days as a US senator -- had gathered in the Rose Garden to witness their boss congratulating Trump. But their somber faces weren't reflected in Obama's message of unity going forward.

"Everybody is sad when their side loses an election, but the day after we have to remember that we're actually all on one team. This is an intramural scrimmage. We're not Democrats first. We're not Republicans first. We are Americans first. We're patriots first," Obama said.

"We all want what's best for this country," he went on. "That's what I heard in Mr. Trump's remarks last night. That's what I heard when I spoke to him directly. And I was heartened by that."