Photograph by Ben Alsop

Deafening screams echo off the walls of the large gymnasium at South Carolina State University on this evening in late January. Flashbulbs pop. People jump up and down, shaking hand-lettered signs reading WE WANT CHANGE and S.C. STATE LOVES BARACK over their heads. Near the front of the stage, beneath a lectern adorned with a blue STAND FOR CHANGE banner, an army of camera-phone-wielding teens and twentysomethings jockey for position as a handsome black man appears.

Ladies and gentlemen, please welcome…Usher!

The man who's sold nearly ten million copies of his 2004 album, Confessions, takes the stage sharply dressed in a gray sweater, jeans, and a khaki jacket with the collar popped. After exchanging hugs with Chris Tucker, actress Kerry Washington, and South Carolina State Representative Bakari Sellers, he grabs a microphone and begins to pace.

"Listen, it's such a pleasure to be here for this cause today." Over scattered calls of "I love you, Usher!" and "That's right, Usher!" he launches into a spirited five-minute sermon that's part civil-rights lesson, part locker-room motivational speech, and part Tony Robbins self-help seminar ("Those blocks we build in our lives, tear them down -- they plague us every day in our personal lives"). It's well meaning if not always terribly coherent, but the crowd gets the gist, and when Usher introduces the night's main attraction -- "Are you guys ready to unleash that power? Are you ready for change? Are you ready for Senator Barack Obama?" -- the junior senator from Illinois gets a reception nearly as enthusiastic as the singer's own.

Obama strides onto the stage, embraces his celebrity coterie, poses with them for a few photos, and then pauses, head bowed, for several minutes while they make their way out of the gym. "I'm going to wait until they get out of here," he tells the crowd. "They might cause a riot."

There is something undeniably disconcerting about watching the first African American with a genuine shot at becoming leader of the free world palling around with the star of Rush Hour 3 and the guy who sings "Yeah!" But it's not exactly surprising. In 2008, this is how you run for president.

Al Jolson may have been the first popular musician to throw his hat into the partisan political ring when he wrote and performed campaign songs for Warren Harding ("Harding, You're the Man for Us") and Calvin Coolidge ("Keep Cool and Keep Coolidge") in the 1920s. Frank Sinatra, along with the rest of the Rat Pack, came out in a big way for John F. Kennedy in 1960, appearing at rallies, organizing shows, and even recording a new version of "High Hopes" ("Everyone wants to back Jack… / 'Cause he's got high hopes!"). The '60s saw a general awakening of the political consciousness of artists across the musical spectrum, though that activism was more often directed toward causes -- against the Vietnam War, for civil rights -- than in support of specific candidates. That began changing in the early '70s. In 1972, Warren Beatty organized fundraising concerts for Democratic presidential nominee George McGovern featuring James Taylor, Barbra Streisand, Simon & Garfunkel, and others. Four years later, the Allman Brothers and the Marshall Tucker Band helped Jimmy Carter raise money for his long-shot presidential bid, while the Eagles, Jackson Browne, and Linda Ronstadt did the same for California Governor Jerry Brown.