The second amendment to the articles of agreement was signed in 1978. It legally formalized the free-floating acceptance and gold demonetization achieved by the Jamaica Agreement, and required members to support stable exchange rates through macroeconomic policy. The post-Bretton Woods system was decentralized in that member states retained autonomy in selecting an exchange rate regime. The amendment also expanded the institution's capacity for oversight and charged members with supporting monetary sustainability by cooperating with the Fund on regime implementation. This role is called IMF surveillance and is recognized as a pivotal point in the evolution of the Fund's mandate, which was extended beyond balance of payments issues to broader concern with internal and external stresses on countries' overall economic policies.