Members of the Oakland Police department form a line during a confrontation with Occupy Oakland demonstrators near the Oakland Museum of California in Oakland, California January 28, 2012. (STEPHEN LAM/REUTERS)
Occupy Oakland demonstrators confront a line of police officers during a demonstration in attempt to occupy a vacant building near Laney College in Oakland, California January 28, 2012. Police fired tear gas at hundreds of Occupy Oakland protesters who tried to take over a shuttered convention center on Saturday, arresting 19 people in the latest clash between anti-Wall Street activists and authorities in the California city. (STEPHEN LAM/REUTERS)
Occupy Oakland demonstrators shield themselves from an exploding tear gas grenade during a confrontation with the police near the Oakland Museum of California in Oakland, California January 28, 2012. Police fired tear gas at hundreds of Occupy Oakland protesters who tried to take over a shuttered convention center on Saturday, arresting 19 people in the latest clash between anti-Wall Street activists and authorities in the California city. (STEPHEN LAM/REUTERS)