Final Solutions: Mass Killing and Genocide in the Twentieth Century (Ithaca: Cornell University Press, 2004).
"Just War and Unjust Soldiers: American Public Opinion on the Moral Equality of Combatants," Ethics in International Affairs, Vol. 33, No. 4 (Winter 2019), pp. 411-444. With Scott Sagan. The same issue includes a symposium on the article with reactions by Michael Walzer, Jeff McMahon and Robert Keohane.
"Animals Are People Too: Explaining Variation in Respect for Animal Rights," Human Rights Quarterly, Vol. 41, No. 1 (February 2019), pp. 39-65. With Yon Soo Park.
"Not Just a War Theory: American Public Opinion on Ethics in Military Combat," International Studies Quarterly, Vol. 62, Issue 3 (September 2018), pp. 548–561. With Scott Sagan.
"Revisiting Hiroshima in Iran: American Attitudes about Nuclear Weapons and Non-Combatant Immunity," International Security, Vol. 42, No. 1 (Summer 2017), pp. 41–79. With Scott Sagan.
"Atomic Aversion: Experimental Evidence on Taboos, Traditions, and the Non-Use of Nuclear Weapons." With Scott Sagan and Daryl Press. American Political Science Review, vol. 107, no. 1 (Winter 2013).
"The True Costs of Humanitarian Intervention: The Hard Truth Behind a Noble Notion." Foreign Affairs, vol. 90, no. 6 (November/December 2011), pp. 60-73.