Final answer:
The Taft-Hartley Act of 1947 significantly amended the Wagner Act to limit the powers of labor unions, including banning certain union practices and enabling "right-to-work" laws.
Step-by-step explanation:
The Wagner Act, also known as the National Labor Relations Act, was amended by the Taft-Hartley Act in 1947 to limit unions' powers. The Taft-Hartley Act introduced several restrictions, including bans on closed shops and union shops, prohibitions on secondary boycotts, and limitations on the use of union funds in political campaigns. It also required union leaders to disavow any ties to Communist organizations and granted presidential authority to delay strikes affecting national interests. Importantly, it allowed states to pass "right-to-work" laws, which further constrained union organization methods.