Young black activists roared their approval when Barack Obama recently greeted criticism on the trail by dusting off his shoulders, a reference to a rap song by Jay-Z called "Dirt Off Your Shoulder." The media covering the moment went crazy, too. Washington Post reporter Teresa Wiltz hailed Obama's moves and called it a "seminal moment in the campaign, the merging of politics and pop culture," and noted the lyrics suggest, "If you feelin' like a pimp ... go and brush your shoulders off."

So Barack Obama is feeling like a pimp?

Online at "The Root," a Washington Post website for African-Americans, Obama supporter and Princeton professor Melissa Harris-Lacewell was sky-high. "Like every other hip-hop generation voter in America I went crazy when he did it," she wrote. "I almost couldn't believe it. It was a perfect moment."

Harris-Lacewell read that moment as a sign of racial swagger and solidarity with "his base of young urban brown and black voters," and they loved it. "He displayed all the familiar self-assurance and bravado of the hip-hop emcee. The people who got it went nuts, while those who don't know hip-hop just thought he was being funny and confident."

The video went viral and became a YouTube sensation.

What is it about this music that drove Obama to emulate it, and drove the Princeton professor crazy in the process? This Jay-Z song boasts about a "middle finger to the law." Harris-Lacewell touted that Obama would like the song "99 Problems," which has an entire verse about being racially profiled by the "mother f---ing law" for "doing 55 in a 54." Jay-Z also tells critics to kiss his whole (rectum).

Sen. Obama claims to be a fan of Jay-Z and Kanye West, but he knows that he has to distance himself a little from the lyrical lows of this "art." He's been gently critical in interviews. "I love the art of hip hop. I don't always love the message of hip hop," he said. Even with the rappers he loves, "There's a message that is not only sometimes degrading to women; not only uses the N-word a little too frequently; but also something I'm really concerned about, it's always talking about material things."

"A little too frequently?" This is like saying a tsunami's a little too wet.

Obama should take a look at a new report from the Parents Television Council about three popular rap-music programs that air in the afternoon or early evening -- "Sucker Free" on MTV and "Rap City" and "106 & Park" on Black Entertainment Television for two weeks in December and a week in March.

In 41 and a half hours studied, analysts found 282 uses of the N-word. Is that "a little too frequently," too?

A little too much degrading of women? In those same hours, there were 143 uses of the B-word to describe women.

A little too much focus on material things? Here, Obama is gliding by the question of what material things are acquired. The rap shows included 205 depictions or discussions of drug sale or use and other illegal activity during the study period, for an average of 7.5 instances per hour, or roughly one instance every eight minutes.

Obama did not discuss the heavily sexualized world of rap in his answer. Sexually explicit scenes or lyrical references on these shows appeared 27 times an hour in December and 40 times an hour in March. No one could miss that drumbeat.

In just one week of programming -- 14 hours in March -- PTC analysts found 1,342 instances of offensive/adult content, or 95.8 instances per hour, or one instance of adult content every 38 seconds.

Who is being influenced by these messages? During the two-week December 2007 study period, children under 18 made up roughly 40 percent of the audience for these three BET and MTV rap programs. Because all of these programs re-air throughout the day, study results underestimate the percentage of unique children who are exposed to this flood of sexually explicit and violent and crime-glamorizing rapper swagger.

A year ago, Obama made an obvious point when he said Don Imus was fired by NBC for using degrading words that are all over rap radio, but rap mogul Russell Simmons cried foul: "What we need to reform is the conditions that create these lyrics. Obama needs to reform the conditions of poverty."

That is, of course, ludicrous. Poverty doesn't "cause" violent gangsta rap any more than road rage is caused by Toyota. These messages are vile and contemptible, and black leaders like former Gov. Doug Wilder and Bill Cosby are true heroes for saying so, while suffering the inevitable blowback.

And Barack Obama is dusting off his shoulders to the applause of the crowd.

Food for thought.