The right of workers in private employment to form unions and bargain collectively with their employers is guaranteed by the National Labor Relations Act (NLRA) and related federal laws. The NLRA is preemptive, meaning that it supersedes state law in the areas that it covers. For example, the Washington Court of Appeals ruled that a former employee could not proceed with his claim that he was discharged for refusing to engage in unfair labor practices (Kilb v. First Student Transportation, LLC, No. 39564-9-II (Wash. App. Ct. 2010)). In this case, the former employee claimed that he was discharged when he disobeyed his employer's directives to fire prounion employees and to engage in other antiunion tactics. The court ruled that it had no jurisdiction to hear the claim because the former employee's state law claims were based on conduct covered by the NLRA.
Although the NLRA supersedes state law covering the same areas, states are free to enact their own provisions dealing with areas not covered by the NLRA, such as the rights of public employees and the rights of private employees who are not engaged in interstate commerce. There is additional information on Washington law in areas not covered by the NLRA.