From KJZZ.org:
Tom Jenney is the Arizona director of Americans for Prosperity, a group which organizes grassroots support for various causes. Dr. David Meyer is professor of Sociology and Political Science at UC Irvine and the author of The Politics of Protest: Social Movements in America. Jenney says protest movements aren't a tool just for the right or left, they're for anyone who feels powerless or as though their rights have been violated. He says successful protests are fundamentally organic. Meyer disagrees and says organizations help some of the most successful protests. Meyer says a successful protest raises an issue and induces elected officials to take action. He says people protest when they feel voting isn't having the effect they want it to. Meter says when people organize they begin to learn from one another and mobilize to get politician's attention.

Audio link available at http://www.kjzz.org/content/1208/what-makes-protest-successful.