<Tr> <Th_colspan="2"> Major amendments </Th> </Tr> <Tr> <Td_colspan="2"> Labor Management Reporting and Disclosure Act </Td> </Tr> <P> The Labor Management Relations Act of 1947 29 U.S.C. § 141 - 197, better known as the Taft--Hartley Act, (80 H.R. 3020, Pub. L. 80--101, 61 Stat. 136, enacted June 23, 1947) is a United States federal law that restricts the activities and power of labor unions . The act, still effective, was sponsored by Senator Robert A. Taft and Representative Fred A. Hartley, Jr., and became law despite U.S. President Harry S. Truman's veto on June 23, 1947 . Labor leaders called it the "slave - labor bill" while President Truman argued that it was a "dangerous intrusion on free speech", arguing that it would "conflict with important principles of our democratic society". Nevertheless, after it passed Truman relied upon it in twelve instances during his presidency . The Taft--Hartley Act amended the National Labor Relations Act (NLRA; informally the Wagner Act), which Congress passed in 1935 . The principal author of the Taft--Hartley Act was J. Mack Swigert, of the Cincinnati law firm Taft, Stettinius & Hollister . </P> <P> Historian James T. Patterson concludes that: </P>

Who was the principle author of the law that was intended to amend the national labor relations act
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