States often use reservations to modify their treaty obligations. Prior research demonstrates why states enter reservations and why states object to reservations, but little work explains why states withdraw them. We argue that states withdraw reservations in response to international social pressure. Using novel data on reservations and reservation withdrawals for the nine core international human rights treaties, our analyses reveal two factors that compel states to withdraw reservations: (1) pressure from peer states and (2) pressure from human rights treaty bodies conducting periodic reviews. While previous work emphasizes domestic factors, our research shows that the international community encourages states to withdraw reservations and strengthen their commitments to human rights and international law.

Despite evidence that United Nations peacekeeping is a cost-effective tool for addressing civil and interstate conflict, it has consistently experienced financial shortfalls as member states neglect to pay their dues. To enable investigation into the dynamics of peacekeeping support, we present newly collected data on all member-state financial contributions to all UN peacekeeping operations from 1990 to 2010. The data also include dues assessed by the UN to gauge the extent to which states fall short of what they owe. We show that financial shortfalls are widespread and vary across both missions and contributors. The data offer opportunities to understand patterns of financial support for peacekeeping across states, missions, and time, and can ultimately provide insight into the factors that lead states to support international institutions and public goods. We illustrate how scholars can use the data with an analysis of the factors that drive states to meet their financial commitments. We find that wealthier states, those more engaged in global trade, democracies, and those that also contribute personnel to peacekeeping operations are the most likely to pay their dues. Conversely, the United States and countries in the Americas, Africa, and Asia are more likely to shirk part or all of their financial obligations in a given year.

States often file reservations to human rights treaties with the goal of reducing their legal commitments under the treaty. Other states within the treaty have the right to declare objections in response to states making reservations. This is a potentially powerful tool for objecting states, and has numerous consequences for relations within and outside the human rights institution. So why do only some states lodge formal objections, while others do not? We argue that states consider the degree of social power they wield over a reserving state when formulating the decision to lodge an objection, because higher levels of social power amplify the effects of an objection. To evaluate our expectation, we gather data on all states’ reserving and objecting behaviors within the Convention Against Torture. Controlling for a number of factors, we find that the measure of social power significantly increases the likelihood that a state will object to another state’s reservation. This research calls attention to the power of objections as a legal tool, and suggests areas of future research for the effects of objections on the legality of human rights agreements.

  • Passmore, Timothy JA, Megan Shannon, and Andrew Hart. 2018. "Rallying the Troops: Collective Action and Self-Interest in UN Peacekeeping Contributions." Journal of Peace Research 55(3):366-379.

Is the acquisition of personnel for UN peacekeeping missions susceptible to free-riding by UN member states? If so, what drives this behavior and what impact does this have on obtaining required personnel for the mission? Using data from 21 missions in 13 African countries between 1990 and 2010, this article addresses whether UN peacekeeping missions experience a shortfall in personnel due to incentives to free-ride by contributing states. It argues that as the number of states contributing to a mission increases, contributors have a greater incentive to free-ride and make suboptimal personnel contributions, leading to greater overall shortfall in the mission’s personnel. However, this free-riding behavior can be mitigated by the economic incentives of contributor states. The findings support two central tenets of collective action theory: that free-riding by member states contributing to the mission is more prevalent when the number of contributors is larger, and when selective incentives such as economic gains are lower. These findings have implications for the strategic composition and efficacy of peacekeeping forces. More broadly, the results underscore the struggle of international organizations to obtain compliance from member states in achieving their international objectives.

  • Hultman, Lisa, Jacob D. Kathman, and Megan Shannon. 2016. "United Nations Peacekeeping Dynamics and the Duration of Post-Civil Conflict Peace." Conflict Management and Peace Science 33(3):231-249.  Winner, Palmer Prize for Conflict Management and Peace Science Article of the Year.

How do the qualities of United Nations peacekeeping operations (PKOs) influence the duration of peace after civil wars? Recent work shows that UN peacekeeping extends the duration of peace. However, this work has only been able to assess whether the presence or absence of UN missions affects post-conflict peace processes. Such analyses offer little in the way of policy prescriptions for planning and structuring PKOs to effectively pursue their goals. By employing fine-grained data on the personnel composition of PKOs, and generating expectations from rationalist bargaining models of civil war, we argue that the number and type of personnel deployed to a PKO influence the UN’s ability guarantee peace by addressing the information and commitment problems that so often lead to the collapse of post-conflict peace. We analyze how the composition of missions influences the duration of peace, finding that, as the number of UN military troops deployed increases, the chance of civil war recurring decreases. However, other personnel types do not have the same effect. We conclude that the effectiveness of post-conflict peacekeeping lies in the ability of PKOs to alleviate commitment problems through the deployment of military troops that are able to defend the peace.

  • Shannon, Megan, Clayton Thyne, Amanda Dugan, and Sarah Hayden. 2015. "The International Community's Reaction to Coups."  Foreign Policy Analysis 11(4):363-376. Noted on The Monkey Cage

With ten attempts since 2010, coups d’état are surprisingly common events with vital implications for a state’s political development. Aside from being disruptive internally, coups influence interstate relationships. Though coups have important consequences, we know little about how the international community responds to these upheavals. This paper explores what drives global actors to react to coups. Our theory differentiates between normative concerns (e.g., protection of democracy) and material interests (e.g., protection of oil exports) as potential determinants of international responses to coups. We argue that coups against democracies, coups after the Cold War, and coups in states heavily integrated into the international community are all more likely to elicit global reaction. Using newly collected data, we explore the number of signals that states and IOs send to coup states from 1950 to 2011. The analyses reveal that coups against democracies and wealthy states draw more attention. States react when democracies are challenged by coups, while IOs react to coups in Africa and coups during the post-Cold War period.  We surprisingly find that heavy traders and oil-rich states do not necessarily receive more reaction, suggesting that international actors are more driven by normative concerns than material interests when reacting to coups.

  • Hultman, Lisa, Jacob Kathman, and Megan Shannon. 2014. "Beyond Keeping Peace: United Nations Effectiveness in the Midst of Fighting." American Political Science Review 108(4):737-753A blog post about this paper can be found at the Early Warning Project. Our work was also mentioned in a summary in Global Policy of research on UN effectiveness in civil wars. It is also covered in a Washington Post blog post by Lise Howard on the effectiveness of UN peacekeeping. Replication data.

While United Nations peacekeeping missions were created to keep peace and perform post-conflict activities, since the end of the Cold War peacekeepers are more often deployed to active conflicts. Yet, we know little about their ability to manage ongoing violence. This paper provides the first broad empirical examination of UN peacekeeping effectiveness in reducing battlefield violence in civil wars. We analyze how the number of UN peacekeeping personnel deployed influences the amount of battlefield deaths in all civil wars in Africa from 1992 to 2011. The analyses show that increasing numbers of armed military troops are associated with reduced battlefield deaths, while police and observers are not. Considering that the UN is often criticized for ineffectiveness, these results have important implications: if appropriately composed, UN peacekeeping missions reduce violent conflict.    

Does United Nations peacekeeping protect civilians in civil war? Civilian protection is a primary purpose of UN peacekeeping, yet there is little systematic evidence for whether peacekeeping prevents civilian deaths. We propose that UN peacekeeping can protect civilians if missions are adequately composed of military troops and police in large numbers. Using unique monthly data on the number and type of UN personnel contributed to peacekeeping operations, along with monthly data on civilian deaths from 1991 to 2008 in armed conflicts in Africa, we find that as the UN commits more military and police forces to a peacekeeping mission, fewer civilians are targeted with violence. The effect is substantial—the analyses show that, on average, deploying several thousand troops and several hundred police dramatically reduces civilian killings. We conclude that although the UN is often criticized for its failures, UN peacekeeping is an effective mechanism of civilian protection.