Final answer:
The Taft-Hartley Act of 1947 is the law that introduced the injunction as a tool for management to combat union activities, marking a stark reversal of prior pro-union legislation.
Step-by-step explanation:
The law that created a new weapon in management's arsenal for combating union activities, specifically the injunction, is the Taft-Hartley Act. Passed by Congress over President Truman's veto in June 1947, this act significantly restricted the powers of unions. Not only did it ban closed shops and union shops, requiring employees to join unions before being hired or as a condition of employment, but it also banned secondary boycotts and limited union spending in political campaigns. One of its most important features was granting presidential authority to postpone strikes that might affect national interests. This act clearly represented a pushback against the Wagner Act of 1935, also known as the National Labor Relations Act, which had supported the rights of workers to organize and bargain collectively.
The correct answer is a) Taft-Hartley Act. The Taft-Hartley Act, passed in 1947, created a new weapon in management's arsenal for combating union activities: the injunction. This act restricted the powers of unions and imposed several requirements on labor unions, including the ban on closed shops and union shops, and the requirement for union leaders to sign affidavits disclaiming any affiliation with Communist organizations. It also granted presidential authority to postpone any strike that might affect national interests for up to eighty days.