SAN FRANCISCO (AP) – The California Supreme Court has upheld a law that labor activists say is key to helping farmworkers improve their working conditions. The 2002 law allows California to order unions and farming companies to reach contracts if the sides are at an impasse. A mediator can impose a contract on the employer that sets wages and other working conditions. The court said Monday that the law didn’t violate the state Constitution. The ruling came in a lawsuit pitting one of the largest U.S. fruit farms, Gerawan Farming, against the United Farm Workers of America, the union that Cesar Chavez helped launch. Labor activists say the law prevented employers from stalling contract talks to avoid a deal. Opponents called it government overreach that deprived employers and workers of any say over wages and other terms of employment.