Yf Reykers

• PhD
• Professor (Assistant) at Maastricht University

Ad hoc coalitions (AHCs) are an indispensable but scantly conceptualized part of global governance. In recent years, several typologies and classifications of global governance arrangements have been provided, mostly differentiating them based on their organizational design features of degree of formality and membership composition. These do not ca...

Against the background of a crisis of United Nations (UN) peace operations, military ad hoc coalitions (AHCs) have increasingly gained a foothold as conflict management tools. This article provides the first comprehensive empirical mapping of military AHCs, focusing on the following questions: how have military AHCs evolved over time, where have th...

North Atlantic Treaty Organization’s (NATO’s) active cooperation with non-governmental organisations (NGOs) on the protection of civilians (PoC) challenges the academic assumption that NATO’s decision-making structures are generally closed to civil society participation. What explains the decision of NATO officials to work with NGOs when developing...

Armed conflicts, pandemics or natural disasters often necessitate rapid, coordinated responses by international organisations (IOs) to avoid escalation or loss of life. However, effective analytical tools to assess and compare the speed of these responses are lacking. This paper introduces a framework for evaluating IO crisis response speed, with t...

Ad hoc forms of military cooperation have become commonplace in European security and defence. The EU has even voiced the ambition to strengthen mutual support between its CSDP operations and European-led ad hoc coalitions. We ask whether and how this mutual support is strengthened and what it means for European defence integration. We focus on two...

The article uses the case of the development of the European Union Battlegroups to the Rapid Deployment Capacity (RDC) to better understand the changing learning capacity of the EU in its military Common Security and Defence Policy (CSDP). The article develops a theoretical framework to capture the most significant factors affecting learning by dra...

Launching multinational peace operations are time and politically sensitive decisions that frequently involve the use of force. As a result, a host of accountability issues arise. To date, mainly backward‐looking and hierarchical accountability measures have been developed to guide the implementation of multinational peace operations led by the mos...

How do status-seeking governments in small states mobilize parliamentary support for participation in US-led warfare coalitions? We argue that the formulation of official invitations by the United States plays an overlooked instrumental role in the domestic ratification game. Invitations can be a strategic tool for governments confronted with divid...

The international response to armed conflict in Africa often takes the form of a regime complex characterized by institutional proliferation, overlap, unclear hierarchies, and multiple interconnections. At the same time, the course of conflict is hardly predictable. In such an environment, how can component units (institutional fora) of a regime co...

Process-tracing is a single case study method that allows students to use within-case evidence to explain a specific outcome that they are interested in and/or to test a theory for some general phenomenon or relationship in the social world. The method offers the tools to either test the explanatory value of a given causal theory or to develop a ca...

Previous research has shown that staffing of international organisations (IOs) is politics. Understaffing of IOs, by contrast, has hardly received scholarly attention. By drawing upon the principal-agent model and refining the concept of "principal slack", we explain why member states-as principals-might not provide the required resources to an IO...

This article examines the conditions under which non-governmental organisations (NGOs) gain access to defence administrations when campaigning for transparency around the use of military force. We theorise that gaining access in this traditionally secluded domain is a matter of supply and demand. NGOs can gain access through technical and political...

While a comprehensive body of research provides evidence that politics does not always stop at the water’s edge, the question “when does politics stop at the water’s edge” has remained largely unanswered. This article addresses this gap in the literature by examining the level of agreement in Belgium’s parliament on military deployment decisions. M...

This paper asks: to what extent can a dedicated or special committee with access to classified information empower parliaments to oversee major defence procurement decisions? These decisions often involve a mixture of political, military, economic and societal interests. Particularly after episodes of contestation or controversy, questions tend to...

While the increasingly thick web of global, regional and sub-regional security arrangements and institutions has received ample scholarly attention, the phenomenon of ad hoc military coalitions and how they impact these institutions has been relatively little explored. We examine ad hoc coalitions in international security responses and develop a t...

Updated version of our previously uploaded paper (forthcoming chapter) with minor number fixes.

Why do small states actively contribute to US-and NATO-led military operations? The small state literature has recently developed a novel explanation, referring to their dependency upon the alliance hegemon. The logic is that the small states aim to improve their status and reputation in order to remain relevant and to receive protection. This arti...

This article studies civil-military relations in defence procurement. Applying insights from the principal-agent model, we argue that decision-making about defence procurement is inherently vulnerable to agency problems. Given the technical nature of these dossiers, governments and parliaments are often heavily dependent upon military expertise, cr...

This article studies the European Union (EU) Military Planning and Conduct Capability (MPCC), which was established in June 2017 and holds the strategic command of EU non-executive missions. While this is the closest the EU has ever come to a permanent military headquarters (HQ), the MPCC has not yet attracted much scholarly attention. This article...

The track record of military rapid response mechanisms, troops on standby, ready to be deployed to a crisis within a short time frame by intergovernmental organizations, remains disappointing. Yet, many of the obstacles to multinational actors launching a rapid and effective military response in times of crisis are largely similar. This book is the...

This article examines the impact of parliamentary involvement in troop deployment decisions on restrictions on military mandates by examining the Belgian contribution to the 2011 Libya intervention and the coalition against the self-proclaimed Islamic State. More specifically, we analyse (1) the effect of party ideology on mandate preferences, and...

Is the United Nations Security Council (UNSC) capable and willing to hold accountable the forces which it authorizes? Although it is an often-voiced recommendation that the UNSC should step up its accountability efforts, such as by installing more strict reporting requirements to avoid mission creep, evaluations of the effectiveness thereof remain...

This article investigates the drivers of the parliamentarisation of war powers. Building on recent findings in the study of war deployments, we argue that the existing literature has predominantly focused on parliamentary drivers of parliamentarisation, leaving potential executive interests untouched. To fill this gap, we propose a rational choice...

Despite the decades of theorization, the causal processes in-between acts of delegation and agency discretion and autonomy are still not developed theoretically, with much ambiguity about how the model’s elements are causally connected. This chapter shows that process-tracing is a useful methodological tool for improving our theoretical and empiric...

Although numerous regional (security) organisations have implemented UNSC-authorised military operations, we do not yet know which considerations prevail in the decision to work through a particular organisation. This article introduces a framework consisting of a capacity, legitimacy and hegemony logic for explaining the selection of a regional or...

Military rapid response mechanisms are generally understood as troops that are on standby, ready to be deployed to a crisis within a short time frame. Yet, the overall track record of the existing multinational rapid response mechanisms within the European Union, the African Union, and North Atlantic Treaty Organization remains disappointing, and t...

This article reviews the gloomy saga of the EU Battlegroups, focusing on four questions: Where do they come from? What do they look like? What have they been hindered by? And where do they go from here? It builds upon earlier findings in the literature and adds novel insights based on original data. In doing so, the article pays particular attentio...

The United Nations Security Council’s (UNSC) oversight over mandate implementation by the regional organizations and coalitions it authorizes is strongly characterized by processes of selectivity. Yet, little is known about these processes. Why is the stringency of these reporting requirements so diverse? And why is compliance to these reporting re...

This chapter assesses the explanatory power of the Principal–Agent (PA) model with regard to inter-organizational relationships in the United Nations (UN) context by focusing on the relationship between the UN and regional organizations, as framed by Chapter VIII of the UN Charter. The introduction of this model to the study of international relati...

Mandate compliance in UN Security Council (UNSC)-authorized operations that involve the use of force remains ill-addressed. This article aims to explain autonomy by conceptualizing the UNSC as a principal who delegates the use of force to an agent. Using process-tracing methodology, it meanwhile confronts the principal-agent model to closer logical...

Although the sad track record of the EU Battlegroups has attracted considerable scholarly attention, analyses have largely focused on obstacles related to the provision of the Battlegroup troops and to the consensus within the EU Council, hence taking a supply-side perspective. This article calls for complementing this perspective with an analysis...

Russia’s behaviour in the United Nations Security Council remains poorly understood. Applying principal-agent insights, this article analyses the Russian abstention towards Resolution 1973, which authorised intervention during the 2011 Libya crisis. Introducing a triangle of delegation, it shows that preferences diverged regarding the means and aim...

How can the European Union (EU) remain a relevant and effective power in a multipolar world? Past studies have sought to address such questions through a focus on the internal constraints the EU faces in its foreign policy. Instead we propose leaving the beaten path by stressing the need for a stronger inclusion of the external perspective in the E...

This paper explores the limits and opportunities of relying on voting data to measure regional leadership in the United Nations (UN) context. Choosing the European Union (EU)’s functioning at the UN General Assembly (UNGA) as case study, it shows that these opportunities are limited for various reasons, notably because of the functioning of both th...