Nicole Gaudiano

USA TODAY

WASHINGTON — Sen. Bernie Sanders acknowledged the obvious for the first time Wednesday, saying “it doesn’t appear” he’ll be the Democratic presidential nominee.

The Vermont senator, speaking during a C-SPAN interview, said his presidential campaign is negotiating on an “almost on a daily basis” with presumptive Democratic nominee Hillary Clinton’s team, urging her to stake out the most progressive positions she can on campaign finance reform, health care, higher education, the economy and raising the minimum wage.

Sanders said he and Clinton have had “real differences of opinion.” But he said he'll do everything he can to defeat presumptive GOP nominee Donald Trump, who he said is "unfit" to be president, and to bring as many people into the political process as possible.

“Where we are right now with Secretary Clinton, we're negotiating, and negotiations go two ways," Sanders said during a wide-ranging hour-long interview with C-SPAN's Steve Scully. "What our job is now is to have her listen to what millions of people in this country who supported me want to see happen, and we'll see how that evolves.”

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Also Wednesday, Sanders announced he will give a speech in New York on Thursday on "where we go from here." He also paid a visit to the House floor, where Democratic members staged a sit-in to demand a vote on gun legislation.

During the interview, Sanders didn’t address the status of his campaign. But when asked whether he'll have a speaking role at the Democratic National Convention in July, he said, “It doesn’t appear that I’m going to be the nominee, so I’m not going to be determining the scope of the convention.”

He didn’t answer a question about whether he'll endorse Clinton but said there's no agreement for him to endorse her before he’s given a speaking slot at the convention.

“It would be nice to speak at the Democratic National Convention,” he said. “If they, for whatever reason, don’t want me to speak, so what? I expect that I will speak.”

Sanders was noncommittal when asked whether he would switch from being an independent to the Democratic Party, even though his campaign has said he is a Democrat and will remain one for life.

"Let’s see what happens right now," he said, adding that he's doing his best to develop a progressive platform.

Sanders said he’s working to revitalize American democracy and boost involvement in the Democratic Party through open party primaries that would allow independents to vote.

“I think it is fair to say, that the Democratic platform will be by far the most progressive platform in the history of the Democratic Party” in terms of economics, climate change, criminal justice, immigration reform, higher education and many other areas, he said.

He also said the role of superdelegates -- party leaders and elected officials who can vote for the candidate of their choice at the convention -- must be reformed so their votes reflect the will of voters from their states.

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The interview offered Sanders’ most extensive remarks since his live, online address to supporters on Thursday night about the next phase of his campaign.

Sanders hasn’t suspended his presidential campaign, even though Clinton has secured enough delegates to clinch the Democratic nomination and the primary season has ended. He has vowed to take his campaign to transform the party to the convention.

After meeting with advisers on June 12, he came close to an acknowledgement that he would not be the nominee.

"We are going to take our campaign to the convention with the full understanding that we’re very good in arithmetic and that we know who has received the most votes up until now," he told reporters then.

During the C-SPAN interview Wednesday, Sanders said Clinton hasn’t talked to him about the vice presidency or sought his advice on a choice. He said she should go with the most progressive candidate and that it would be “a terrible mistake” if she chose someone who has been “backed by Wall Street.”

Asked whether he could work with her if she's elected president, he said “it really depends issue by issue.” He added that he would work with Clinton “where she is prepared to stand up and fight for working people and take on big-money interests.”

Sanders, who said he has known Clinton for 25 years, recalled how impressed he was with a speech she delivered, without notes, as first lady on the “enormously complicated” health care plan she helped develop while her husband, Bill Clinton was president.

He described the former secretary of state as “very intelligent,” saying that Clinton has had to fight “a lot of sexism” and that she's far ahead of Trump in command of policy. But Sanders also qualified his praise, saying “there are areas where we have strong disagreements.”

“She is more or less an establishment Democrat,” he said. “It’s kind of hard to deny that. And I think we’ve got to move beyond that.”

Reacting to Trump's statements that Sanders' supporters are welcome to join the presumptive GOP nominee's campaign, Sanders said, "I suspect he ain't going to get too many of those people."

"The vast majority of people who voted for me understand that Donald Trump in a dozen different ways is literally unfit to be president of the United States," he said, adding that Trump has made "bigotry the cornerstone of his campaign."

As for his future, Sanders said it’s “a little too early” to talk about his next Senate campaign but he has no reason to think he won’t continue, if his constituents still want him to serve.

“But we’ve got an election in front of that, before that one,” he said.

Sanders didn’t hesitate when asked which committee he would like to chair if Democrats win back the Senate majority in the fall: the Health, Education, Labor and Pensions Committee. Sanders said the committee works on important issues and its Democratic members are “pretty progressive.”

"(It) deals with the issues that I’ve been involved in my whole life, that I feel very strongly about,” he said.

Sanders acknowledged that Sen. Patty Murray, D-Wash., the committee's current ranking member, is next in line for the chairmanship among Democrats. Murray's spokesman, Eli Zupnick, said Murray won't be making any decisions until after the election but "loves the work she is doing" on the committee and "there is a whole lot more that she’d like to get done."

Sanders, reflecting on his campaign, smiled while looking at photos of the massive crowds that attended his rallies. He appeared to tear up watching a clip of his “America” TV ad, saying it gives him “tingles” each time he sees it.

He said his campaign was “an educational experience” for a “small-town guy” who goes home to Vermont on weekends and previously hadn’t spent much time with people in the Latino community. He said he had to learn "a whole lot" about immigration reform, the need for criminal justice reform and the "decimation" that happens in African-American communities when fathers are in jail.

“What goes on in police relationships in Vermont is very, very different than what goes on in inner cities all over this country,” he said. “People are being brutalized, people are fearful of police.”

Sanders said he always thought he could become the nominee, though he acknowledged he was “one of the few people in the world who believed that."

“I thought we had a message that could resonate,” he said. “The speed at which it resonated surprised me.”

Sanders said his campaign made mistakes, though he didn’t specify any. And he said he's proud of winning 22 states and more than 12 million votes.

“The regret is we should have been smarter,” he said. "On the other hand, we were right about so many things.”