With five days left until the Democratic primary in South Carolina, the Bernie Sanders campaign faces a dire situation. Hillary Clinton leads in the Southern state by over 20 points, according to the RCP average, which means that Sanders might be looking at his first blowout loss of the primary season. According to a Fox News poll last week, Hillary has a 40-point advantage over Bernie among black voters. Spike Lee wants to change that — in a hurry:

The battle for African-American celebrity backing and voters continues to be a major part of the Democratic nominating contest this week. And the Bernie Sanders campaign will start running radio ads today in South Carolina featuring another famous voice: Spike Lee.

“Waaaaake up! Wake up, South Carolina!” Lee begins in the new spot first obtained by ABC News from the Bernie Sanders campaign. “This is your dude, Spike Lee. And you know that I know that you know that the system is rigged! And for too long we’ve given our votes to corporate puppets. Sold the okie doke. Ninety-nine percent of Americans were hurt by the Great Recession of 2008, and many are still recovering.

“That’s why I am officially endorsing my brother, Bernie Sanders. Bernie takes no money from corporations. Nada. Which means he’s not on the tape, and when Bernie gets into the White House, he will do the right thing!” the actor, writer and film producer continues in the ad.

Lee’s ad also notes that Sanders was with “Dr. King … in the March on Washington,” and had been arrested as a protester in civil-rights demonstrations. The ad doesn’t mention it, but it serves as an implicit rebuke of civil-rights legend Rep. John Lewis, who dismissed Sanders’ commitment to the cause two weeks ago. “I never saw him, I never met him,” Lewis said of his time leading the the Student Nonviolent Coordinating Committee from 1963-66, “but I met Hillary Clinton. I met President Clinton.” Later, it turned out Lewis actually hadn’t met them at that time, but the discrepancy didn’t get much attention from the media.

Will this be enough to move the needle among African-American voters in South Carolina? It would take a miracle to pull that off, but that may not necessarily be the first objective with this ad. The so-called SEC primary comes up in one week, with Southern states choosing presidential favorites in both parties. Lee’s ad could be adapted for other states — Waaaaaake up, Georgia, Virginia, Alabama, Tennessee! — and almost certainly will be. One has to wonder whether Lee might be preparing a television ad along the same theme, given his talents as a filmmaker, and that might start to shift opinion, too. The problem for Sanders and Lee is that it still probably won’t be enough, as polling in the Southern states shows him in much the same position as he is in South Carolina … twenty or more points behind across the board.

Nevertheless, the split in backing might demonstrate vulnerabilities for Hillary in a key Democratic demographic. If those gaps begin to narrow — and if the barbs about Hillary getting bought by “billionaires” stick — that could portend a very difficult general election campaign if Hillary hangs on to win the nomination.