This book improves our understanding of battlefield coalitions, providing novel theoretical and empirical insight into their nature and capabilities, as well as the military and political consequences of their combat operations. The volume provides the first dataset of battlefield coalitions, uses primary sources to understand how non-state actors of varying types form such groupings, reports interviews with policymakers illuminating North Atlantic Treaty Organization operations, and uses cases studies of various wars waged throughout the nineteenth, twentieth, and twenty-first centuries to understand how other such collectives have operated. Part I introduces battlefield coalitions as an object of study, demonstrating how they are distinct from other wartime collectives. Using a novel dataset of actors fighting in 492 battles during interstate wars waged between 1900 and 2003, it provides, for the first time, a comprehensive portrait of the universe of battlefield coalitions. Part II explores processes and dynamics involved in the formation of battlefield coalitions, addressing how potential coalition members prepare for future battles in peacetime (as well as the consequences of such preparations) and the dynamics of mission design. Part III focuses on how battlefield coalitions are organised and fight when combat ensues, notably their decision-making rules and practices, command structures, and learning capacities. Part IV addresses three curious tendencies observed in the operations of battlefield coalitions: partners under-providing effort in combat, rebels and terrorist networks persisting in cooperation even when their interests diverge, and members defecting from the collective. Part V concludes with a chapter outlining for future researchers what we know about battlefield coalitions and what remains to be understood. This book will be of much interest to students of military and strategic studies, defence studies and International Relations.

Successful strategies effectively use force, directly or indirectly, to secure and advance broader political objectives. While it is not always necessary to achieve military victory over the adversary to succeed strategically—for example, Henry Kissinger famously noted that the guerrilla wins as long as he does not lose—it is often required. Recognizing the importance of military victory for attainment of strategic goals, belligerents often form “battlefield coalitions,” or groups of officers, troops, and materiel brought together by multiple distinct political communities for the purpose of jointly waging combat in the same operational battlespace. That is, in the hope of increasing their chances of military victory, they deploy their forces side-by-side with those fielded by a partner and the combined formation then works in concert at the operational and tactical levels of war to defeat the adversary in discrete battles.

This book explains how military coalitions form, as well as their implications for war, peace, and the spread of conflicts.

The mechanism for the operation of our military forces beyond the shores of the U.S. is the modern coalition from the grand alliance of NATO to simple bilateral relationships. Understanding the dynamics of coalition warfare is important for a U.S. Military that often finds itself operating as the dominant member of any coalition it joins. One of the major considerations listed in the portion of joint doctrine which addresses multinational coalitions is the concept of unity of effort Current U.S. Army doctrine has long recognized the importance of unity of command. However, the latest drafts of the new Army keystone doctrine publication, FM 100-5, have upgraded the principle of unity of command to unity of effort. The efficacy of this change recognizes the realities of operations in a world of coalitions, trans-governmental agencies, and private organizations all which find themselves often in league with our military as we strive to reach common (not always strictly military) objectives. This monograph will examine two historical case studies from the Napoleonic Wars (1792-1815) in order to explore the relationship between tactical and doctrinal differences between different members of the same coalition. The first case study examines the coalition army of Marshal Suvorov at the battles of the Trebbia and Novi in 1799. The second example will move forward in time to the Russo-Prussian army of the spring of 1813 and its performance at the battles of Lützen and Bautzen. Although history does not provide us with exact recipes for implementing complex solutions in a complex world, it does provide a means to understand the dynamics of human behavior on a vast scale. The Napoleonic period represents a veritable laboratory of coalition warfare and provides a means of applying the lessons of a historical period to understanding the dynamics of coalitions.

The mechanism for the operation of our military forces beyond the shores of the United States is the modern coalition from the grand alliance of NATO to simple bilateral relationships. Understanding the dynamics of coalition warfare is important for a United States Military that often finds itself operating as the dominant member of any coalition it joins. One of the major considerations listed in the portion of joint doctrine which addresses multinational coalitions is the concept of unity of effort. Current U.S. Army doctrine has long recognized the importance of unity of command. However, the latest drafts of the new Army keystone doctrine publication, FM 100-5, have upgraded the principle of unity of command to unity of effort. The efficacy of this change recognizes the realities of operations in a world of coalitions, transgovernmental agencies, and private organizations all which find themselves often in league with our military as we strive to reach common (not always strictly military) objective. This monograph will examine two historical case studies from the Napoleonic Wars (1792-1815) in order to explore the relationship between tactical and doctrinal differences between different members of the same coalition. Specifically the effect of these differences on the unity of effort, both military and political, will be addressed. The first case study examines the coalition army of Marshal Suvorov at the battles of the Trebbia and Novi in 1799. The second example will move forward in time to the Russo-Prussian army of the spring of 1813 and its performance at the battles of Lutzen and Bautzen. Although history does not provide us with exact recipes for implementing complex solutions in a complex world, it does provide a means to understand the dynamics of human behavior on a vast scale.

What accounts for variation in the military performance of coalitions and alliances on the battlefield? This dissertation presents and tests a realist-institutionalist theory of coalition military effectiveness, which accounts for both the process of capability aggregation within military coalitions and its implications for coalition fighting effectiveness. It posits that variation in the design of coalition institutions for political-military planning, command relationships and information exchanges significantly affects the ability of member nations to fight alongside each other on the battlefield. According to the theory, coalition military institutions provide the key mechanisms through which coalition members manage intra-alliance uncertainties and fears, thereby allowing for closer coordination of their war effort. The most effective military coalitions adopt joint political-military coalition planning, unity of command with an integrated command staff, and the fluid exchange of information among coalition nations. The study tests this theory through a mixed-methods approach, complimenting a medium-n statistical analysis with two detailed case studies of coalition wars fought under conditions chosen to provide maximum theoretical leverage. The medium-n statistical analysis examines all interstate coalition wars waged between 1816 and 2007 using the Correlates of War Inter-state War Data (version 4). Using primary documents, memoirs and battle histories, the study tests realist-institutionalist theory in two empirical cases: France and Britain in the First World War (1914-1918) and France and Britain in the Battle of France (May-June 1940). The main finding is that variation in the design of coalition military institutions accounts for differences in coalition battlefield effectiveness both across and within coalitions over time. The study makes three principal contributions. First, it offers the first serious treatment of coalition military effectiveness in the academic literature. Unlike other research, it expands beyond national military effectiveness to consider the coalition dimension. Second, the study contributes to a growing body of research suggesting the importance of non-material variables to explanations of military effectiveness, drawing attention to the critical importance of coalition military institutions for combat power. Finally, the study informs the public policy debate, suggesting whether the US and other allies could achieve battlefield success more quickly, with fewer casualties and at lower costs if it acted through ad-hoc military coalitions or institutionalized alliances.

Some of the most brutal and long-lasting civil wars of our time involve the rapid formation and disintegration of alliances among warring groups, as well as fractionalization within them. It would be natural to suppose that warring groups form alliances based on shared identity considerations - such as Christian groups allying with Christian groups - but this is not what we see. Two groups that identify themselves as bitter foes one day, on the basis of some identity narrative, might be allies the next day and vice versa. Nor is any group, however homogeneous, safe from internal fractionalization. Rather, looking closely at the civil wars in Afghanistan and Bosnia and testing against the broader universe of fifty-three cases of multiparty civil wars, Fotini Christia finds that the relative power distribution between and within various warring groups is the primary driving force behind alliance formation, alliance changes, group splits and internal group takeovers.