San Francisco police officers will stay alert Tuesday for any crimes or disturbances at polling stations or ballot boxes, said department spokesperson Evan Sernoffsky. Barring unforeseen chaos, the department will not dispatch police to stand at or guard any polling places — California law prohibits such police presence, without written authorization from the city or a county elections official.

As dusk settles and the polls close, San Francisco will beef up patrols to control crowds and contain any civil unrest.