SAN FRANCISCO -- On both sides of San Francisco Bay, the liberal mayors of two famously liberal cities have found themselves struggling to balance their avowed support for the Occupy Wall Street movement with the need to preserve public safety. The spirit of the movement has strong allies in Oakland Mayor Jean Quan and San Francisco Mayor Ed Lee, both of whom have ties to social activism in the area. Quan, a former student activist at University of California, Berkeley, during the 1960s, had stood one year ago between police and police-shooting demonstrators in an unsuccessful attempt to calm the...