Imports pour into the United States, up by 79 percent in six years. The trade deficit more than doubles. The House of Representatives solidly rejects a bill that would liberalize global and regional trade and endorses import quotas for a major manufactured product by a two-to-one margin. Although at first glance these events of the 1990s might sound like past chapters of US trade politics, in fact the political dynamics have changed in significant ways. As the impact of globalization comes into focus, politically important constituencies have begun to resist trade liberalization. Labor and environmental groups in particular, demanding that their concerns be addressed, have succeeded in fracturing the long-standing, bipartisan, protrade coalition in Congress, and in the process have undercut US leadership in liberalizing global trade.This new study reexamines the landscape of trade politics. It shows how trade advocates and labor and environmental skeptics differ significantly in both their substantive views and their political and organizational cultures. The authors demonstrate how this new challenge differs from that of traditional trade protectionism, likening it instead to the debate a century ago over whether and how to regulate American capitalism for social purposes. The analysis leads to a set of recommendations aimed at constructive compromise and a new political foundation for US trade policy leadership.