The Labor-Management Relations Act, informally the Taft-Hartley Act, is a Unite States federal law greatly restricting the activities and power of labor unions. The Act, still effective, was sponsored by Senator Robert Taft and Representative Fred A. Hartley, Jr. and legislated by over-riding U.S. President Harry S. Truman's veto on June 23, 1947; labor leaders called it the "slave-labor bill" while President Truman argued it would "conflict with important principles of our democratic society" despite subsequently using it twelve times during his presidency. The Taft-Hartley Act amended the National Labor Relations Act (NLRA; informally the Wagner Act), which Congress passed in 1935.