Emerging from the White House after meeting with Obama for 45 minutes, Sanders said he wasn't bothered by a recent interview in which Obama appeared to be tilting toward his former secretary of state.
"I think he and the vice president have tried to be fair and even-handed in the process, and I expect they will continue to do that," Sanders said.
And while Sanders hasn't embraced Obama's agenda as much as Clinton has, he said Wednesday that on most issues, he hews closely to the White House's views.
"There's no secret that we have, as is the case in a Democratic society, we have differences of opinion," Sanders said. "I was on the floor of the Senate disagreeing with him over taxes. We disagree over (the Trans-Pacific Partnership trade deal). By and large, over the last seven years on major issue after major issue, I have stood by his side to where he has taken on unprecedented Republican obstructionism, has tried to do the right thing for the American people."
Sanders was seen arriving to the West Wing alongside his wife, Jane, and his spokesman, Michael Briggs, just after 11:30 a.m. ET Wednesday. His meeting with Obama was the first time the former Senate colleagues have held a substantive discussion since Sanders' candidacy began surging in early voting states, a come-from-behind boost that some have compared to Obama's own race against Clinton in 2008.
White House Press Secretary Josh Earnest said after the meeting ended that Sanders and Obama likely shared stories from the campaign trail, allowing the President to "reminisce a little bit about his own experience campaigning for president -- both in terms of drawing big crowds, but also spending some time talking to people in more out-of-the-way places."
And he characterized the ongoing battle for the Democratic nomination as positive for the President's party.
"It's good for the Democratic Party for there to be such a robust debate going on about who should be our party's nominee," Earnest said.
In Iowa, which holds the first nominating contest of the 2016 race on Monday, Sanders and Clinton are running in a dead heat, polls show.
Despite the apparent similarities between Obama and Sanders' Iowa runs -- including their pull with young voters -- the President rejected any comparison in an interview taped last week.
"There's no doubt that Bernie has tapped into a running thread in Democratic politics that says: Why are we still constrained by the terms of the debate that were set by Ronald Reagan 30 years ago?" Obama told Politico
. "You know, that has an appeal, and I understand that."
But Obama soon moved on to praising Clinton, who he deemed ready to begin governing as soon as she assumed the job.
"She can govern and she can start here, Day 1, more experienced than any non-vice-president has ever been who aspires to this office," Obama said, clearly tilting toward his former secretary of state but avoiding a full-fledged endorsement.
Speaking at the CNN Democratic Town Hall on Monday, Clinton said she was "really touched and gratified"
when she read Obama's quote.
She added that the relationship between the one-time rivals had "turned into a real friendship."
Meeting had been scheduled in advance
Both Sanders' campaign and the White House said Wednesday's sit-down has been scheduled for some time.
The meeting with Obama had been on the books "for days," Sanders' spokesman Briggs told CNN.
Obama, who the White House says will not endorse a candidate in the Democratic primary but will campaign for the eventual nominee, is watching the current election with an eye toward his legacy. Many of his most sweeping actions have been accomplished through executive order, making the next president critical in carrying out his agenda.
When Obama said earlier this month he would withhold his support for any political candidate that didn't support "common sense" gun control laws, it was widely regarded as a rebuke of Sanders, who has voted for provisions that would protect firearm manufacturers from liability after shooting deaths. Later, the White House noted that Sanders' said he would revisit his position following Obama's warning.
Clinton, meanwhile, has largely embraced Obama's record on the campaign trail, touting his health law as a game-changer for uninsured Americans and accusing Sanders of planning to scrap it. A number of Obama's former aides now work for Clinton's campaign, and the President is personally closer to the candidate who served in his administration for four years.
Earnest said Wednesday that Obama has consciously attempted to remain neutral in the Democratic nominating contest, but that he does plan to vote absentee in Illinois' primary on March 15.
Obama and Clinton last met in December for lunch. The White House did not disclose the session ahead of time, and said afterward it was mostly a "social occasion." It was the latest in a long series of meetings between the two former colleagues, both at the White House and on Martha's Vineyard, where both of their families spend time in August.
Clinton, in her many visits to the White House, has chosen to enter and exit out of sight of reporters.