A paper by the American Bar Association on National Labor Relations Act Basic Law and Procedures as it applies to the Postal Service:

Labor relations in the Postal Service is governed by Chapter 12 of the Postal Reorganization Act of 1970 (hereafter “PRA”), 39 U.S.C. 1201 et seq. Prior to passage of the PRA, the wages and benefits of postal employees were set by Congress and the only influence that postal unions could exert was as legislative lobbyists. Private-sector collective bargaining was the product of legislation following on the historic Postal Strike of 1970, which lasted from March 18 to March 25, 1970. At its peak, the strike involved over 200,000 employees. The strike effectively shut down the postal service and precipitated a declaration of a national emergency by President Nixon, who called on the military to help move the mail.
The negotiations which ended the strike culminated a Memorandum of Agreement between the postal unions and the Nixon Administration on April 16, 1970, which recited that
“the parties have jointly developed, through the collective bargaining process, proposed legislation” to restructure of the Post Office Department, and for wage raises and improvements in working conditions. It also called for “collective bargaining over all aspects of wages, hours and working conditions including grievance procedures, and in general, all matters that are subject to collective bargaining in the private sector,” but continuing the “[b]an on federal employee strikes [with] binding arbitration” of contract disputes. In addition, the “National Labor Relations Board [was] to supervise representation elections and enforce unfair labor practices.” H.Rep. 91-1104, 91st Cong. 2d Sess. 57-59 (May 19, 1970). President Nixon’s April 16, 1970, Message to Congress transmitted the agreed-upon legislation. Id. at 51. The law which is now the PRA, Public Law 91-375, was ultimately adopted on August 12, 1970.

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