A more thorough explanation:

The Labor–Management Relations Act is a federal law that was passed in 1947. It regulates certain activities of labor unions, allows lawsuits against unions for certain actions, prohibits certain strikes and boycotts, and provides steps for resolving strikes during national emergencies. It is also known as the Taft–Hartley Act.

The National Labor Relations Board is an independent federal agency with five members. Its purpose is to prevent and remedy unfair labor practices and protect employees' rights to form labor unions. The board investigates complaints of unfair labor practices and can issue orders that can be reviewed or enforced by a U.S. court of appeals. It was created by the National Labor Relations Act of 1935.

For example, if a union engages in a strike that is deemed illegal under the Labor–Management Relations Act, the employer can sue the union for damages. The National Labor Relations Board would investigate the complaint and issue an order if necessary. This helps to ensure that both unions and employers follow the law and treat employees fairly.