Why is Bernie Sanders appearing on 'Ellen'?

Sanders’s seriousness contrasted with DeGeneres’s affability – sounds like talk segment gold, right? And it kind of was.

Bernie Sanders is set to appear on “The Ellen DeGeneres Show." It’s true – the white haired, slightly angry presidential hopeful from Vermont taped an interview on Wednesday with host Ellen DeGeneres for her popular syndicated show. He even traveled to Los Angeles to do it.

Sanders’s seriousness contrasted with DeGeneres’s affability – sounds like talk segment gold, right? And it kind of was. Senator Sanders came out dancing to “Disco Inferno” – a ’70s track that features the lyric, “burn, baby, burn,” which can be inferred to mean “Bern, baby, Bern,” – get it? Or maybe we should say he came out making dance-like movements coordinated with different music he was hearing in his head.

Sanders seemed to enjoy it, though, so the whole thing came off without him looking silly.

“You’re dancing Bernie, that’s fantastic,” said Ms. DeGeneres.

“Thank you for the very positive energy you provide to the American people,” said Sanders in response.

He and DeGeneres then went through a fairly quick summary of the economic basis of his campaign – the growth of inequality and so forth. Sanders said he’d never run a negative campaign ad. DeGeneres said the Democratic debate was more civil than its GOP counterpart. They traded an awkward amalgam of fist bump and handshake. DeGeneres called it “Trump-like” and insisted they do it right.

DeGeneres asked which Republican candidate Sanders would pick to be stranded with on a desert isle. Sanders chose Florida Sen. Marco Rubio.

“He’s used to the sun,” he said.

The biggest laugh came when the host asked Sanders if he’d ever been in handcuffs, and he replied, quickly, “yes."

At first the Vermonter didn’t quite get the humorous response – perhaps he thinks “Fifty Shades of Grey” is about a retiree bus trip.

“When I was protesting at a civil rights rally, I was arrested,” he explained.

“OK, he’s calling it a ‘civil rights’ thing,” said Ellen.

You can watch the whole episode for all the details. But we’re actually interested in a meta question: What was Sanders doing on “Ellen” in the first place?

He’s not a normal politician, after all. In the past he’s gotten angry at reporters who asked what he considered frivolous questions, such as whether he has an opinion on Hillary Clinton’s hair. It’s no knock on DeGeneres to point out that frivolity is her substance. She comes at things from an angle. She challenged Michelle Obama to a push-up contest. Her show is not exactly the “News Hour” with couches.

We can think of two reasons why this might make sense for Sanders. One is obvious: The audience for “Ellen” skews female, and Sanders needs to attract more women voters. He’s competing with Mrs. Clinton, the potential first female president, and she does better with members of her gender than he does. Her net favorable rating among Democratic women voters is 57, according to Gallup. Sanders’s is 34.

Among male Democrats, their favorable ratings are about equal, at 44 percent.

The second is slightly less obvious to those of us who think about politics all day (though probably not to you). Sanders just needs to be better known. Compared with Clinton, he’s obscure to the electorate at large, and popular entertainment talk shows are one of the few places where politicians can appear in front of a mass US audience not predisposed to think about Wall Street regulation.

He’s doing better in this regard. Sanders is now well-known to 60 percent of Democrat voters, according to Gallup, up from 49 percent in July. But Clinton is well-known to over 90 percent of Dems. So Sanders has some catching up to do. If his “Bern Baby Bern” dance video goes viral, it would help.