Here's a protest primer:
"1913 Massacre," Woody Guthrie
"A Change Is Gonna Come," Sam Cooke
"Masters of War," Bob Dylan
"Ringing of Revolution," Phil Ochs
"Mississippi Goddam," Nina Simone
"Ballad of Sacco & Vanzetti," Joan Baez
"Man in Black," Johnny Cash
"The Revolution Will Not Be Televised," Gil Scott-Heron
"What's Going On?" Marvin Gaye
"Sunday Bloody Sunday," U2
"Washington Bullets," The Clash
"Little Man with a Gun in his Hand," Minutemen
"Flowers of Guatemala," R.E.M.
"Black Steel in the Hour of Chaos," Public Enemy
"Talkin' 'bout a Revolution," Tracy Chapman
"Lost Woman Song," Ani DiFranco
"Killing in the Name," Rage Against the Machine
"Fijate Bien," Juanes
"What the Po-Pos Hate," The Coup
"The Revolution Starts. . . Now," Steve Earle