Since the early 20th century, the United States of America has served as the backbone of the contemporary world order in which we live today. However, political scientists still have to travel a long road before understanding why the USA has come to move away from non-interventionism towards interventionism the way it did. This study seeks to fill this void. By utilising computerised textual analyses of all Congressional speeches made by the successive Presidents of the USA, this study first shows the development of the USA’s foreign affairs agenda during the post-Civil War period. Next, it underscores the impact of the USA’s military capacity on the interventionist development of the USA’s foreign affairs agenda during this period by conducting a non-classical statistical analysis, and by accounting for alternative explanations.

Dongwook Kim is Lecturer in Political Science in the School of Politics and International Relations at the Australian National University. He received his PhD from the University of Wisconsin-Madison. Prior to coming to the ANU, Dr Kim was Hewlett Postdoctoral Fellow in the Center on Democracy, Development, and the Rule of Law at Stanford University, and taught at the University of Chicago as Lecturer in International Relations and at Marquette University as Assistant Professor of Political Science in the USA. His research and teaching interests include International Relations theory, human rights, international law and organizations, transnational nongovernmental activism, policy diffusion, and mixed-methods research design. His research has appeared in International Organization, European Journal of International Relations, and Journal of East Asian Studies.

Woo Chang Kang is a lecturer at the School of Politics and International Relations at the Australian National University. He received his PhD from New York University. Prior to joining the ANU, he was a postdoctoral associate at the Council on East Asian Studies, Yale University. His research specializations include pork barrel politics, voter behaviours, and public opinion. His work appears in Electoral Studies, Conflict Management and Peace Science, Journal of East Asian Studies and other academic journals.