I study the domestic politics of international security: why democracies differ in military involvement, how parliaments and parties shape decisions on the use of force and military assistance, and how foreign policy changes, most recently in work on Germany’s Zeitenwende and European responses to Russia’s war against Ukraine. At VU Amsterdam I lead the work package on foreign-policy contestation in the NEST project, where we surveyed attitudes on military assistance in the Netherlands and across Europe in 2025.
My methods-related work focuses on Qualitative Comparative Analysis (QCA) as a set-theoretic method for descriptive and causal inference. My books include Democratic Participation in Armed Conflict and Qualitative Comparative Analysis: An Introduction to Research Design and Application, and I’m co-editor of the Routledge Handbook of Foreign Policy Analysis Methods.
You can find my publications, research, teaching, PhD supervision, talks, outreach, and CV on this site. Please feel free to reach out.
Upcoming
- December 7–9, 2026
European QCA Conference, IHS, Erasmus University Rotterdam. Annual meeting of the QCA community, with various method and paper workshops. - December 2026 / January 2027
Registration opens for the QCA summer school course in Lugano (August 2027, pending confirmation). For impressions from previous years, see here.
Latest updates
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European Geoeconomics Workshop at University of Amsterdam
On October 14, I took part in the workshop “European Geoeconomics: The Political Economy of Geopolitics in Europe” of the Amsterdam Centre for European Studies (ACES) at the University of Amsterdam, where Wolfgang Wagner and I presented our paper “Public Opinion, Party Politics, and Military Support for Ukraine: Voter-Party Congruence and Vote Switching”. Continue reading →
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R Manual for QCA, version 4.2
Version 4.2 of the R Manual for QCA adds expanded sections on visualizing results, with templates for creating, customizing, and combining X–Y plots, along with new sections on cluster analysis and robustness tests following the protocol of Oana and Schneider. The manual now runs to 44 pages, with an accompanying R script and sample data. Continue reading →
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Ten Years of QCA at the Lugano Summer School
For the eighth time, I taught “Exploring Causal Complexity with Qualitative Comparative Analysis (QCA)” at the Summer School in Social Sciences Methods in Lugano, ten years after the first edition of the course. The intensive one-week course combines lectures with hands-on exercises in R, participant presentations and individual consultations. Continue reading →
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Uncovering Causal Symptoms Discussed at AQMMR workshop
Hilde van Meegdenburg and I presented our co-authored book manuscript “Uncovering Causal Symptoms: Case Study Research, Process Tracing, and Qualitative Comparative Analysis” at the AQMMR workshop of the Institute for Qualitative and Multi-Method Research at Syracuse University, where it was discussed by James Mahoney and Ingo Rohlfing. Continue reading →