Tom Morello, Mos Def Narrowly Avoid a Riot at Minnesota's Take Back Labor Day Concert

As the Take Back Labor Day concert opened on Harriett Island in St. Paul, Minnesota, Billy Bragg's cover of Laura Nyro's "Save the Country" drifted over a hot, sluggish Mississippi River and mixed with the lingering traces of tear gas from outside the RNC. The Mississippi divided two very different scenes: On the south bank, a sold-out crowd of 20,000 college-age kids, 30-something parents and kids stood in the 90-degree heat and clapped along to "There Is Power in Our Union," while on the north bank, "anarchist" ninjas smashed windows at Macy's and led riot police on a chase through downtown streets practically devoid of Republican delegates.

Back on the other side of the river, news of the violence — marring an otherwise peaceful protest march 10,000 strong — Twittered through the audience as Steve Earle and wife Alison Moorer ended their set with a duet of "City of Immigrants." Union officials took the mike between acts to rally the crowd around the flag of the Service Employees International Union, which sponsored the event.

Tom Morello, in his solo, Nightwatchman mode with a guitar emblazoned "Whatever It Takes," played "One Man Revolution" and a bluesy version of "Guerilla Radio" before bringing a dozen veterans from Iraq Veterans Against the War onstage to lead the crowd in "This Land is Your Land" with the "secret, censored" verses intact.

The crowd swelled when hometown heroes Atmosphere appeared onstage with live keyboards and back-up singers. Rocking an Obama '08 T-shirt, Slug started out by dedicating the overzealous cop ballad "Less One" to the police. Later, as Mos Def moved through an almost-constant stream of dub and soul tinged favorites like "Respiration," "Hip Hop" and "Fake Bonanza," he paused for just a second. "Damn, I thought Minnesota was cold," he said, taking off his jacket. "It's hotter than a motherfucker!" He went on to "Undeniable" to New Orleans, which was staring down hurricane Gustav on the other end of the river.

The screen above the stage didn't get a lot of use until the Pharcyde walked out to a spacey CG intro. The four performed "Ya Mama," "4 Better Or 4 Worse" and "Drop" as their classic music videos unspooled behind them. Just as Pharacyde was closing the concert with a cover of "My Prerogative" and "Passing Me By," another Twitter news flash went through the audience: The bridges back into St. Paul were shutting down, effectively turning the Mississippi River into a moat.

The sun dipped behind the trees while security shooed the crowd out of Harriet Island and police sent them towards, supposedly, the only open bridge, on Robert St. "If I see a Republican, I am going to shit," one teenage boy said, crossing the train tracks past the closed Wabasha St. Bridge. When the tired, sun-baked attendees met a phalanx of riot police and police car barricades blocking the foot of the span, the line held fast as hundreds of concertgoers continued to back up on the north side of the bridge, unable to cross.

Some of the friendlier concertgoers milled around and waved at the Coast Guard patrolling the water below in inflatable rafts armed with mounted machine guns. Confused police vehicles ran into their own roadblock — along with a few SUVs and an empty school bus — and they were soon enveloped in the crowd. For a few minutes, a riot seemed imminent. Chanting and screaming broke out and the crowd began to press forward before the St. Paul Police realized their mistake and let them leave. Once freed, the masses broke into applause and then dispersed into the deserted streets of a deserted convention. One officer turned to another in disbelief, "I can't believe we did this," he said.