Historical events have set the stage for the current U.S. agricultural export performance. Agricultural exports in the early 1990s were as large or larger relative to the size of the agricultural sector than at any time since. A dramatic decrease in net farm income was caused by the Great Depression (1929-1932). Following passage of the Hawley-Smoot Tariff Act and the wave of protectionism it set off around the world, U.S. agricultural exports remained small until the early 1970s, when devaluation of the U.S. dollar and a surge in world demand for agricultural commodities returned agricultural exports to their predepression level. U.S. agriculture is now inextricably linked to world markets. Five issues and developing trends in world agricultural markets have the potential to shift current world patterns of agricultural trade: (1) the current round of multilateral trade negotiations; (2) higher value product trade trends; (3) the scheduled 1992 economic integration of the European Community; (4) foreign development assistance; and (5) the United States-Canada Free Trade Area Agreement. Maintaining and enhancing U.S. competitiveness in world markets is tied to continued efforts to liberalize world trade and adequate allocation of funds to research in the production, processing, and marketing of food and agricultural commodities. (18 figures; 17 references) (YLB)