Desertion—the title of this deftly argued work—aptly describes its focus. Political scientist Theodore McLauchlin (Univ. of Montreal[1]), has written extensively, in both English and French, on the intersection of civil wars and desertion in modern conflicts across Europe, Asia, Africa, and the Middle East. In this, his first monograph, he seeks to explain why some combatants stay in the fight while others run away. The book centers on soldiers of the Spanish Civil War (1936–39), fought between defenders of the Republican government and an alliance of right-wing Nationalist revolutionaries. It resulted in a decisive victory for the forces of Gen. Francisco Franco, ushering in a long period of fascist rule. While McLauchlin has much to say about the military narrative specifically of that conflict, his larger purpose is to use it as a data set to test his theories about desertion in civil wars.

Previous studies analyzed factors that influence soldier behavior. Combatants are often bound by shared commitments to a cause, a desire to support their comrades, or the unifying process of recruitment, training, and military life. Even coercion may figure in enforcing discipline and participation. Though he admits the importance of these mechanisms, McLauchlin stresses a "relational approach." What matters most are the links between soldiers and their perceptions of others' motivations: "bonds of trust among combatants keep them fighting, mistrust pushes them to leave, and beliefs about political commitments and the motivation to fight shape both" (2).

For many years, the debate about whether soldiers fought for a cause or their comrades dominated scholarly literature on the question. More recently, a consensus has emerged that neither factor fully explains soldiers' actions throughout their military experience. In his influential study of the French Revolutionary period,[2] John Lynn specified the categories of initial motivation, sustaining motivation, and combat motivation. While there might be considerable continuity and overlap between these, Lynn's approach makes us mindful of distinctions. The factors that encouraged soldiers to enlist, stick with their unit in times of boredom or despair, or to stand by their comrades in the thick of battle deserve scrutiny in their own right.

After surveying the relevant scholarship, McLauchlin uses his relational approach to bridge the various interpretations. He argues that "norms of cooperation and coercion" (4) are crucial in shaping soldiers' decisions to fight or flee. What concerns him about previous ideas about the causes of desertion are the anomalies. Scholars have identified patterns under which desertion increases, for instance, harsh conditions and strained logistics, and "prospects of defeat" (8). McLauchlin constructs counter-narratives that undercut those assumptions. Soldiers may endure deprivation and the fear of defeat, for instance, when serving in resilient units with strong bonds of trust. By contrast, units with firm group cohesion, strong social homogeneity, or fervent belief in a cause might yet suffer significant desertion. Groups of men in war can encourage each other to shirk or run as readily as stand and fight together. McLauchlin emphasizes bonds of trust and perceptions whether others are willing to sacrifice themselves for shared goals.

The author also considers whether coercion can prevent desertion. Studies of civil wars have shown the value of a carrot-and-stick approach. The desired loyalty is often fostered by a combination of reward and punishment, notably "high payment and strong coercive penalties for deserting" (11). Scholars have suggested, however, that coercion can cause declining morale and acts of resistance. For McLauchlin, the key determinant is trust: "the risk of provocation turns on the same dynamics of mistrust" (34), which nurtures presumptions of guilt and unreliability. Other factors play significant roles: whether a unit is divided by factionalism or "stereotypes" of disloyalty, or punishment is meted out capriciously or unfairly. In the end, coercive methods often backfire and are "not very good even at the intended aim" (34) of reducing desertion. Soldiers are "soft rationalists" seeking their own goals "within a social world with social relationships" (29) rather than isolated automatons.

The author's relational approach highlights the links between ideological motives and the external conditions of soldiering and war. In a chapter on the loyalty of Republican officers facing widespread executions, he explains that

This interplay of trust and coercion in maintaining soldier loyalty is central to McLauchlin's research. On the critical subject of coercion and punishment, he argues that desertion reflects a balance between a "provocation effect [and a] deterrent effect" (35). A soldier's decision to desert is influenced by both the likelihood of punishment or being caught and perceptions of whether coercive actions are justified and impartially ordered by legitimate authorities.

While the author concentrates on the Spanish Civil War, his findings apply to aspects of other civil wars in other contexts as well as soldiers' wartime behaviors in general. He contends that civil wars have a character that sets them apart from international conflicts. Factors of trust and mistrust are more "acute in civil conflicts" (17). Many of their combatants only weakly adhere to their armies or causes, instead focusing more intently on survival and fears that comrades will let them down (3). People caught up in civil war often hide behind "a false front of enthusiasm and conviction" (16).

Rather than a work of political science, as touted by its publisher, McLauchlin's book is a study in military sociology based on a rigorous quantitative methodology. It poses a central research question about trust and desertion in civil wars, outlines the current state of the field and the spectrum of factors pursued in understanding the subject. It tests a series of hypotheses in subsequent chapters on specific periods and focal points—especially desertion—of the Spanish Civil War. These include the prevalence of visible signs of commitment ("costly signals"), the level of social homogeneity vs. factionalism in a given unit, stereotypes of disloyalty, and the application and perceived legitimacy of coercive punishments.

McLauchlin's conclusions extend beyond the Spanish Civil War to establish an approach to desertion in other types and eras of conflict. His salutary relational approach operates at both the micro- and macro-levels. Readers learn about interpersonal relations within military units as well as "what practices and characteristics generate trust and reduce desertion" (17) on a larger scale (17). The author even includes a chapter on his hypotheses and methodologies as they pertain to the complicated landscape of factionalism in the civil war in Syria—a good test case of the value of the relational approach.

"In broad strokes, then, the differences in armed groups' rates of desertion corresponded to how they recruited, managed, and controlled their fighters, and thus to conditions of mutual trust and mistrust within them" (184). In clear and accessible prose, Theodore McLauchlin makes a persuasive, subtle, and well supported case. Desertion: Trust and Mistrust in Civil Wars is a most compelling contribution to the growing field of civil war studies. Readers have much to look forward to in his future work.