Wherever we probe in our study of public opinion and foreign policy, we encounter frustrating complexities and ambiguities. Political theorists and historians disagree about the ways the public ought to influence foreign policy and the dimensions of the actual nature of the relationship in American history. Most contend that presidents are somehow constrained by a public that defines broad national goals and sets parameters for action. Yet the presidents' preeminence in the opinion-making process guarantees them almost as much freedom in the international arena as leaders from less democratic systems. The public itself is not monolithic. Several publics possess varying degrees of knowledge of, interest in, and influence on foreign policy. Individuals develop foreign policy attitudes because of exposure to events and as a result of socioeconomic status and personality development.
The wealth of sophisticated research produced by social scientists since World War II underscores the gaps in knowledge about the opinion-policy relationship. Although we know much more about the origins of foreign policy attitudes, as well as the world of the decision maker, the precise nature of the opinion-policy nexus still eludes us. Because of the questions raised about the meaning of the Vietnam experience for the American democratic system, scholars and statesmen began reexamining the public's impact on foreign policy. As might have been expected, considering the earlier debates over this complicated and contentious issue during the life of the republic, they have failed to reach a clear consensus on this most important and often troubling aspect of their unique political system.