Has AFSCME ever been legally prohibited from striking?

Yes. In 2008, AFSCME leaders called on UC patient care employees to strike at all five UC medical centers. UC petitioned the Public Employment Relations Board, the state agency that oversees public sector collective bargaining, to request a restraining order against the strike on UC's behalf. PERB issued a complaint against AFSCME for bad-faith bargaining and for encouraging employees to strike even though their absence from work would clearly endanger the public's safety. The Superior Court of San Francisco issued a restraining order prohibiting the union's strike.