Rage Against the Machine's militant political stance straddles an equally militant sound. Furious riffs churn out of Tom Morello's guitar and dive into grinding psychedelics -- the American music of opposition. But these are the sounds of a culture that is too angry for '60s passive resistance. The wah-wah pedal is a call to action. The urgency of Zack de la Rocha's frantic podium rants are taken out of the riot directing bullhorn and put into percussive rap poetics. Key to RATM's appeal is their fusion of some of America's most political musical movements: the liberation sounds of funk, the anarchistic resistance of punk, the angry alienation of metal, and the urban exasperation of hip-hop creating a revolutionary synergy on all four studio albums. De La Rocha left the band in 2000 to pursue a solo career while his bandmates went on to form Audioslave with Chris Cornell of Soundgarden on vocals. In 2007, Rage were received with open arms as they re-grouped and returned to performing and politicking.