A United States federal law that greatly restricts the activities and power of labor unions. The Act, still largely in effect, was sponsored by Senator Robert Taft and Representative Fred A. Hartley, Jr. U.S. President Harry S. Truman described the act as a slave-labor bill and vetoed it, adding that it would conflict with important principles of our democratic society. The Senate followed the House of Representatives in overriding Truman's veto on June 23, 1947, establishing the act as a law. The Taft-Hartley Act amended the National Labor Relations Act (NLRA, also known as the Wagner Act), which Congress had passed in 1935.