To Know or Not To Know? Realist and Liberal Theories on Foreign Affairs and Public Opinion in Latin America Rodrigo Morales Castillo, Gerardo Maldonado, and Jorge A. Schiavon We contrast the central theoretical claims of the realist and liberal traditions of interna- tional relations concerning the importance of public opinion in foreign affairs, providing sufficient empirical evidence to uphold the liberal view and refute the realist hypothesis. Using data collected over the last decade by The Americas and The World Project in Brazil, Colombia, Ecuador, Mexico, and Peru, we show that, even if Latin Americans have impor- tant limitations in terms of knowledge of international affairs, a strong system of political beliefs endows them with the conceptual tools to face the complexity of global issues, permitting them to hold coherent and consistent preferences on international issues. El artículo contrasta los postulados teóricos centrales de las escuelas realistas y liberales de las relaciones internacionales sobre la importancia de la opinión pública en los asuntos exteriores, proporcionando evidencia empírica suficiente para defender los axiomas liberales y refutar las hipótesis realistas. Utilizando los datos acumulados en la última década por el proyecto Las Américas y el Mundo en Brasil, Colombia, Ecuador, México y Perú, se demuestra que, a pesar de las limitaciones de conocimiento sobre asuntos internacionales por parte de los latinoamericanos, existe un fuerte sistema de creencias políticas que los dota de herramientas conceptuales para afrontar la complejidad de los problemas mundiales, permitiéndoles mantener preferencias coherentes y consistentes. Key words: public opinion, foreign affairs, foreign policy, Latin America, The Americas and The World, realist theory, liberal theory, knowledge, ideology, shortcuts Introduction A re the nature and complexity of international affairs obstacles to people making judgments well enough informed to allow them to form coherent attitudes on global affairs, as the realists believe? Or rather, as the liberals assert, are such judgments possible even with a lack of information and knowledge? Until very recently—before the 1990s—it was very difficult to answer this ques- tion in Latin America because of the lack of solid, accurate, and systematic Latin American Policy—Volume 6, Number 1—Pages 2–18 © 2015 Policy Studies Organization. Published by Wiley Periodicals, Inc.