High Quality Content by WIKIPEDIA articles! Right-to-work laws are statutes enforced in twenty-two U.S. states, mostly in the southern or western U.S., allowed under provisions of the Taft-Hartley Act, which prohibit agreements between trade unions and employers making membership or payment of union dues or "fees" a condition of employment, either before or after hiring. Prior to the passage of the Taft-Hartley Act by Congress over President Harry S. Truman's veto in 1947, unions and employers covered by the National Labor Relations Act could lawfully agree to a "closed shop," in which employees at unionized workplaces are required to be members of the union as a condition of employment. Under the law in effect before the Taft-Hartley amendments, an employee who ceased being a member of the union for whatever reason, from failure to pay dues to expulsion from the union as an internal disciplinary punishment, could also be fired even if the employee did not violate any of the employer's rules.