Interest groups are the stuff of domestic policymaking. Americans are used to speaking of diverse constituencies: butchers, bakers, candlestick makers, and so on. Members of Congress talk about their districts in terms of these interests. In the words of former Speaker Thomas P. O’Neill, “All politics is local.” On foreign policy, we don’t often think of a variety of interests within the United States. We see the world as “us” against “them.” Especially in international crises, when the stakes are clear and our entire way of life might be threatened, the nation must speak with one voice, not many. There simply doesn’t seem room for interest groups. Yet interest groups have long been active on foreign policy. Group activity has grown increasingly important in recent years as the world has become more interdependent. The new mantra has become “all politics is global.”1 Why has foreign policy been different from domestic policy, and how have things changed?