Here's a debate that strikes a familiar chord. When do song lyrics that are meant to be entertaining hit a sour note and become offensive?

Many conservatives think rap music crosses the line. In 1992, the rapper Ice-T released an album featuring the song "Cop Killer," which President George H.W. Bush called a threat to police officers. After law enforcement associations boycotted his record label, Time Warner, Ice-T pulled the song from the album.

During those skirmishes in the culture wars, you would hear liberals defend the creative process, praise the First Amendment, and dismissively tell anyone who was offended by vulgar lyrics to "get over it" and develop thicker skins. Now those on the left have the chance to show us how it's done and walk it like they talk it.

And it's all thanks to "Barack the Magic Negro," a cheeky parody of "Puff, the Magic Dragon" that pokes fun at the jealousy and resentment that older black leaders initially exhibited toward Barack Obama.

Did you catch that? This is not a song that makes fun of Obama – as some might assume from media reports – but rather one that makes fun of those who claimed that Obama was not being black enough or appreciative enough of the struggles of those who came before him.

Mimicking the voice of the Rev. Al Sharpton, the song – which first aired on Rush Limbaugh's radio show – starts off:

"Barack the Magic Negro lives in D.C.

The L.A. Times, they called him that

'Cause he's not authentic like me.

Yeah, the guy from the L.A. paper

Said he makes guilty whites feel good.

They'll vote for him, and not for me

'Cause he's not from the hood."

The "guy from the L.A. paper" is Los Angeles-based writer David Ehrenstein, who penned an op-ed piece that ran in the Los Angeles Times on March 19, 2007. Ehrenstein, who is African American, wrote that besides running for president, Obama was also "running for an equally important unelected office, in the province of the popular imagination – the 'Magic Negro' … (who is) there to assuage white 'guilt' (i.e., the minimal discomfort they feel) over the role of slavery and racial segregation in American history."

Why is Obama magic? Because like the dragon in the 1960s folk song, Obama is – according to Ehrenstein – not real. Instead, he's "like a comic-book superhero" – "the less real he seems, the more desirable he becomes. If he were real, white America couldn't project all its fantasies of curative black benevolence on him."

That's radical stuff. It's basically a message to white folks that just because they've accepted Barack Obama doesn't mean they're off the hook for more than 200 years of oppression and discrimination against African Americans and other minorities.

That's not the kind of thing you'd normally hear from the Republican National Committee, which finds itself embroiled in this controversy after Chip Saltsman, a former chair of the Tennessee Republican Party who is running for RNC chairman, sent fellow Republicans a CD that included "Barack the Magic Negro." It was a boneheaded thing to do, if Saltsman really wants to lead a party that has managed to scare off or tick off just about every color in the rainbow and now finds itself with an ever-shrinking base of white rural voters.

But it wasn't racist. The racism is coming from those on the left and their simpaticos in the media who twisted this story to fit the narrative of a GOP hostile to minorities. That story line lets the Democratic Party look progressive by comparison – which allows it to rest on its laurels instead of doing its part to improve race relations.

That's how it is in the game of racial politics. Conservatives are often held to higher standards while liberals skate by on what we might call – to borrow a phrase – the soft bigotry of low expectations.