- Reverse Mission: Transnational Religious Communities and the Making of US Foreign Policy (Georgetown, 2011)
- Transnational Catholicism in Postcommunist Europe (Rowman & Littlefield, 2001)
- Catholic Bishops in American Politics (Princeton, 1991)
- Catholic Bishops in US Politics, guest editor, Religions, 2016
- Religion in an Expanding Europe, co-editor. (Cambridge, 2006)
- Abortion Politics in American States, co-editor. (M.E. Sharpe, 1995)
- The Catholic Church and the Politics of Abortion, co-editor. (Westview Press, 1992)
Journal articles and book chapters on religion in world politics:
- Comillas (2024)
- The Geopolitics of Religious Soft Power (2023)
- Uncertainty and its Discontents (2022)
- Journal of Church and State (2020)
- Herder Korrespondenz (2025) (2020), (2019), (2018), (2017)
- Berkley Forum (2019)
- Oxford Research Encyclopedia of Politics (2018)
- Review of Faith in International Affairs (2017) reprinted in Modern Papal Diplomacy and Social Teaching in World Affairs (2019)
- Current History (2008) reprinted in Religion and Foreign Affairs: Essential Readings (2012)
- Transnational Actors in Central and East European Transitions (2008)
- Issue Brief: American Institute for Contemporary German Studies (2007)
- Perspectives on Politics (2006)
- The Catholic Church and the Nation-State (2006)
- The One, the Few, and the Many (2001); The Protection of Religious Minorities in Europe (1999)
- Mitteleuropa: Between Germany and Europe (1998)
- Religion, State, and Society (1997)
- American Review of Politics (1997)
- Tamed Power: Germany in Europe (1997)
- Conscience (1996)
- East European Quarterly (1996)
- Commonweal (1993)
Journal articles and book chapters on religion and politics in the United States:
- OMG! (2017
- National Catholic Reporter (2014)
- Albany Law Review (2007)
- Clergy and Politics (2001)
- Political Science Quarterly (1993)
- Journal of Church and State (1991)
- Do Elections Matter, 2nd ed. (1991)
- Church Polity and American Politics (1990)
Journal articles and book chapters on abortion policy and politics:
- Conscience (2017), (1996)
- Do Elections Matter, 3rd ed. (1996).
Other articles and reviews in various journals.