Abstract
The central question driving my research is twofold: (1) how the preferences of domestic actors are structured, and (2) how these preferences shape their foreign policy attitudes and contribute to broader domestic debates. While scholars widely agree on the importance of domestic politics in international relations, the precise mechanisms through which it operates in foreign policy remain underdeveloped. Many studies in international security and diplomatic relations emphasize broader structural cleavages in domestic politics, such as partisan divisions or electoral dynamics.
While such structural explanations offer parsimony, they often fail to reliably explain domestic behavior in the foreign policy domain. Rather than simply following leaders or adhering to party lines, domestic actors frequently evaluate foreign policy through the lens of their own personal preferences, producing far more diverse patterns of support and opposition. Moving beyond previous aggregate assumptions, this dissertation develops a more nuanced account of domestic politics in foreign policy by investigating the ideological foundations of foreign policy attitudes. Individuals hold distinct beliefs about how their country should respond to various opportunities and challenges in international affairs, shaped by their deeply held ideological beliefs. This dissertation develops a more systematic analysis of the nature of these ideological preferences and how two motivations—partisan and ideological—interact to shape legislative behavior and public opinion on foreign policy in the United States.
Across three essays, this dissertation finds that ideology introduces significant heterogeneity in domestic actors' foreign policy behavior. In the first essay, I develop a novel measure of senators’ foreign policy ideological orientations—estimated along three dimensions: Isolationism-Internationalism, Cooperative Internationalism, and Militant Internationalism—by applying supervised machine learning to classify over 100,000 U.S. Senate floor speeches on foreign affairs from 1947 to 2020. These new measures reveal ideological structures that serve as a distinct and independent source of foreign policy preferences, separate from political incentives.
In the second essay, I show that ideology plays a central role in shaping legislative behavior on foreign policy, challenging aggregate, party-centered models. Parties are not homogeneous blocs; legislators within the same party exhibit far greater diversity of views than conventional models suggest. Moreover, parties do not function as unitary actors driven solely by electoral incentives. Analyzing over 450 roll call votes on arms control and military procurement policies, I find that legislators’ voting behavior aligns more closely with their ideological beliefs than with strategic partisan considerations.
Finally, the third essay—co-authored with Todd Sechser and Sunggun Park—finds a robust and independent effect of shared political ideology on the effectiveness of elite cues. In three pre-registered survey experiments conducted with a nationally representative sample of over 12,000 American adults, we show that the public’s foreign policy views are shaped not simply by in-party loyalty or out-party animus, but also by ideological congruence with elite cue-givers.
Collectively, these essays demonstrate that ideology and partisanship are separate, though intersecting, sources of motivation for domestic actors in foreign policy. A comprehensive understanding of foreign policy decisions requires attention to both strategic political dynamics and enduring ideological preferences that shape how domestic actors interpret and engage with international affairs.
