Tensions between California Nurses Association and the Service Employees International Union ticked up a notch yesterday, when SEIU officials filed a motion in Oakland Superior Court, accusing CNA members of trying to squelch the free speech SEIU members. This all started last month, when CNA members tried to stop SEIU organizers from getting thousands of Ohio nurses to join their union. Angry SEIU members confronted the rival union at a labor meeting in Michigan, and even sometimes outide their homes. Last week, CNA got a court injunction banning SEIU members from harrassing them, and the SEIU is seeking to overturn that injunction. The two unions have been warily circiling each other for years; now, it seems, they're out for blood.