When Kendrick Lamar said “I don’t give a f— about no politics in rap” on last year’s To Pimp a Butterfly, he probably wasn’t talking about the 2016 presidential election. But if he was, some of his peers clearly disagree.

“In my heart of hearts, I truly believe that Senator Bernie Sanders is the right man to lead this country,” Atlanta rapper Killer Mike, born Michael Render, roared to an excited crowd at a November campaign rally in his hometown. Behind him, a woman proudly holding a sign that read “Hotlanta Feels The Bern 2016” cheered on the rapper’s endorsements.

For Sanders, an independent senator from Vermont running for the Democratic presidential nomination, grassroots support like this has been the key to his campaign so far, in “Hotlanta” and the rest of the nation. When Sanders, a self-proclaimed “democratic socialist,” entered the primary race, some wrote off his call for a political revolution as the talk of an outsider candidate destined to stay there.

But nine months later, and just days from the Iowa caucuses, Sanders’ outsider status has brought him closer to the mainstream than ever before. According to a new CNN/ORC poll, he leads Hillary Clinton — long considered the Democratic frontrunner — in Iowa, a surge that few would have expected just months ago.

In fact, it’s a surge that echoes the growth in popularity of another longtime cultural outsider: hip-hop.

While artists supporting candidates is a political tradition, in 2016, rap endorsements like Killer Mike’s are more important than ever. A Spotify study in July claimed hip-hop was the most listened-to genre in the world. And hip-hop’s popularity isn’t just apparent in record sales and song streams; political endorsements by rappers can provide similar buzz for candidates.

When Killer Mike went to an Atlanta soul food restaurant with Sanders, photos of the event went viral online. And who could forget the drama when Lil B dropped Clinton in favor of Sanders — a change that resulted in several lengthy cable news appearances by the Based God in support of his new favorite politician.

Of course, Sanders isn’t the only politician to receive endorsements from hip-hop stars. Clinton, his chief rival in the primary race, has the benefit of immediate celebrity recognition — a perk that has nabbed her support from rap royalty such as 50 Cent, Snoop Dogg and A$AP Rocky. But despite these artists’ relative commercial success (compared to those on the Sanders campaign trail), their words of advocacy often came in the form of inconsequential tweets and interview quips — a far cry from the inspired speeches and interviews of Sanders’ hip-hop allies.

So what is it about the 74-year-old senator — whose musical tastes are more Beethoven than Biggie — that draws endorsements from the likes of Killer Mike, Bun B and Scarface?

For many who support Sanders, it’s about what he says he can do for the country.

“A lot of people started talking to me about Bernie Sanders, and they’re like, ‘You need to pay attention to him,'” said Lil B, who once rapped the Hillary-supporting “B—-, I’m Bill Clinton.” “Bernie was a part of fighting segregation, which was something that really touched my heart … as well as I heard he was for free education, which makes me so happy.”

In a six-part interview with Sanders on Killer Mike’s YouTube channel, the rapper repeatedly mentions how Sanders’ policies would benefit the black community — a message Sanders has struggled to get out on his own.

Vermont, Sanders’ home state, is 95 percent white, a lack of diversity shared by both Iowa (92 percent white) and New Hampshire (94 percent) where polls have him leading. But among black voters, Sanders has struggled; polls show Clinton significantly ahead of Sanders when it comes to nonwhite Democrats.

“I need for my community to understand that your message directly impacts them,” Killer Mike told Sanders in his interview.

And with the help of rappers like Killer Mike and Lil B, who have large fan bases and influence among young black voters, Sanders hopes he can prove to those groups that his ideas are worth voting for. It certainly won’t be easy, but Sanders believes it’s possible.

“Here’s the very good news,” he told Killer Mike. “Everything we have talked about, the vast majority of people — white, black, Hispanic — they’re on our side.”