MSNBC's Rachel Maddow sat down with Sen. Bernie Sanders (I-Vt.) on Wednesday, after his disappointing Super Tuesday, and she wasn't lobbing softballs. "I feel like your argument for your electability is flawless," she said. But actually "expanding the electorate" and "trying to reach a diverse coalition" is "not happening in your campaign, and it's not happening in your campaign more so in your campaign now than it did in 2016. And I want to know if you have any analysis yourself of why that's not improving?"

"We're trying to transform this country, not win an election, not just beat Trump," Sanders said. "So it's a different type of campaign, and we're doing quite well within that context."

Maddow pressed Sanders on his persistent weakness among black voters, especially in the South. Sanders said that he won about 39 percent of people of color — Latinos, Asian-Americans, and black voters — in California, but Maddow pointed out that even in California, Sanders is "being well outpaced by Joe Biden among black voters."

"Well, we're running against somebody who has touted his relationship with Barack Obama for eight years," Sanders said. "Barack Obama is enormously popular in this country in general, and in the African American community. Running against Hillary Clinton, Bill Clinton was enormously popular." Some polls have him beating Biden among black voters, he said, so "it's not that I'm not popular," but Biden's ties to Obama are "working well" for him.

Sanders told Maddow that "if Biden walks into the convention, or at the end of the process, has more votes than me, he's the winner." Maddow asked if it's "100 percent impossible to imagine a unity ticket" with Biden. "You mean two old white guys on the ticket?" Sanders asked. "Well, probably not. ... One old white guy is probably one too many for some. I think we need a little more diversity than that."