Vermont Sen. Bernie Sanders has accepted that he's not going to be president. And he really doesn't want presumptive Republican nominee Donald Trump in the Oval Office.

But that doesn't mean he's willing to endorse former Secretary of State Hillary Clinton, who defeated Sanders in the Democratic primaries.

He's said he will vote for Clinton in November but told MSNBC on Tuesday that his plan to vote for her isn't an endorsement of the candidate. "No, they're not one and the same," he said. "What I am trying to do now, in a variety of ways, is to see that we have a Democratic platform that represents working families, that is prepared to take on the fossil fuel industry and Wall Street."

Throughout his insurgent presidential run, Sanders has called for a "political revolution" that seeks to completely explode politics as usual. His aggressive progressive agenda includes breaking up big banks, replacing Obamacare with a government-run universal health-care system, free public college education and expanded Social Security benefits.

"Our job is to transform America, to end the 40-year decline of the American middle class," Sanders told MSNBC's Andrea Mitchell. "That is what I am fighting to do. And we are in that process right now. We did very well, I thought, in St. Louis, in terms of the first meeting of the platform committee. Now we go to Orlando, and then we go to the floor of the Democratic Convention. Politics is not a baseball game with winners or losers. What politics is about is whether we protect the needs of millions of people in this country who are hurting. That is my focus. And my job right now is to make the Democratic Party as open, as inclusive, as progressive as it possibly can be, and that's what we're working on as we speak."

Mitchell continued to press Sanders about when or whether he would suspend his campaign and endorse Clinton. The Vermont senator gave no ground, pointing out that the Democratic Party must convince Americans that its agenda is the right one for the country.

"You're asking," he said, "I think, with all due respect, Andrea, the wrong question."

-- Douglas Perry