The growth and proliferation of technical and nontariff barriers in agriculture have derived principally from the intervention of government at all levels—local, regional, nationalostensibly to facilitate the trading process, and thereby to increase economic efficiency and to improve agricultural income. Many of the restrictions on trade in modern industrial agriculture provide prime examples of the conflict—import quotas, and variable levies being the most obvious. The growth of so-called nontariff trade barriers since the 1920s represents a new era in protectionism, and their multiplication since World War II has replaced customs duties as the most important form of agricultural trade distortion. In fact, they represent the major threat to both international cooperation and the future of efficient agriculture in the world. The Declaration on the Uruguay Round of General Agreement on Tariffs and Trade by ministers meeting at Punta del Este specifically pointed to nontariff measures and agricultural trade as subjects for negotiations.