ByJohn S. McClenahen The U.S., the EU and Japan need to exercise leadership at the current meeting of trade representatives from more than 140 nations in Cancun, Mexico, or the World Trade Organization conference, which runs through Sept. 14, "is likely to deteriorate into a finger-pointing shouting match," says Kent A. Jones, chair of the economics division at Babson College, Wellesley, Mass. Developing countries also must do their part, recognizing that trade gains come not only from persuading trading partners to open markets but also from developing nations opening their markets to trade and competition, adds Jones. Agricultural subsidies among the world's rich nations pose the biggest challenge to further trade liberalization, Jones believes. "Agricultural subsidies alone in the U.S. and Europe now represent more than the GDP for the entire continent of Africa. Some creative way must be found to end this gravy train, whose benefits go mainly to large corporate farming operations," he states.