In our podcast, Rachel Myrick, the Douglas & Ellen Lowey Associate Professor of Political Science at Duke University, discusses with us how extreme partisan polarization threatens not only domestic governance but also global stability. Drawing on her new book, Polarization and International Politics: How Extreme Partisanship Threatens Global Stability (Princeton University Press, 2025), Myrick argues that polarization in democracies affects foreign policymaking.

The conversation begins with a striking example:each year, the political risk consultancy Eurasia Group publishes a list of the world’s top geopolitical risks. The 2024 report placed as the highest risk not the Russian aggression, Middle Eastern conflict, but ‘the United States versus itself’. This diagnosis, Myrick suggests, encapsulates the central claim of her book: extreme party polarization erodes the institutional foundations that once made democracies stable and credible actors abroad.

Throughout the podcast, the author unfolds how polarization affects the three pillars that democracies used to have in international relations: the ability to keep foreign policystable over time, to credibly signal information to adversaries and the reliability with partners in international politics. Then, the discussion moves to the ways in which polarization affects foreign policies. In a healthy democracy, leaders are incentivized to provide public goods and act in the national interest.Instead, in extremely polarized environments, politicians do not „target messaging at the median voter and instead work to mobilize their political base”. Voters increasingly view politics as a contest between moral enemies rather than legitimate rivals, caring more about their side’s victorythan about performance or accountability.

While the United States provides her primary example, Myrick points to similar patterns across Europe. In younger democracies such as Hungary or Poland, polarisation fuels “executive aggrandizement,” as ruling parties rewrite rules to secure permanent advantage.In established democracies, it simply makes governments less predictable partners internationally. Rachel Myrick ends the conversation with a warning: the greatest threat to international order may no longer come from authoritarian powers, but from democracies unable to govern themselves and to be effective partners.