European Journal of International Security reexamines the causes and effects of NATO enlargement on Russia's relationship with the West, using counterfactual analysis. She wrote a 2017 Council on Foreign Relations report, Reducing Tensions between Russia and NATO, as well as articles on Russian President Vladimir Putin's decision to intervene in Ukraine and his actions towards pre-war Syria and Iran. Her first book, Engaging the Enemy: Organization Theory and Soviet Military Innovation (Princeton University Press, 1993, published under her former name of Kimberly Marten Zisk), received the Marshall Shulman Prize from the Association for Slavic, Eurasian, and East European Studies. The book shows that Soviet military officers from the late 1950s onward engaged in lively debates about how to respond to changes in U.S. and NATO military doctrine in Europe, and spearheaded innovations that led to a doctrine race with the West. Her second book, Weapons, Culture, and Self-Interest: Soviet Defense Managers in the New Russia (Columbia University Press, 1997), explored why Russian defense industrial enterprises struggled so badly when faced with the end of Soviet central planning. She demonstrated that what appeared to be poor decisions in the face of Soviet cultural overhang were actually remarkably adept reactions by defense industrial managers to the incentives of the new market economy; they simply put their own individual interests above the health of their enterprises. She wrote a related article about conflicts in the formerly closed Soviet nuclear city of Arzamas-16 as it adapted to the market economy. Marten's next book, Enforcing the Peace: Learning from the Imperial Past, stepped away from Russia. It argues that UN Security Council authorized peace enforcement operations led by Western countries (in Haiti, Bosnia, Kosovo, and East Timor) bore a remarkable resemblance to the colonial activities of Great Britain, France, and the United States at the turn of the twentieth century. At a time when it was fashionable to say that militaries can't do peacekeeping, she demonstrated that well designed military missions could restore peace to insecure regions and even do policing well; success depended on how they were trained and how missions were prioritized. In a related article she argued that ensuring stability in the target state was necessary before political reforms could be cemented. Her most recent book, Warlords: Strong-Arm Brokers in Weak States (Cornell University Press, 2012, in the Cornell Studies on Security Affairs series), showed why and how “warlords” (armed local power