In August 2014, militants of the self-proclaimed Islamic State descended upon the Yezidi communities of northern Iraq, unleashing one of the most devastating campaigns of mass violence in recent history. Within days, villages across the Sinjar region were emptied—men and boys executed in fields and schoolyards, women and girls abducted and sold into slavery, and thousands forced to flee toward Mount Sinjar, where many perished from hunger and thirst. The intent was unmistakable: the annihilation of a people and the erasure of their faith. The United Nations and numerous human rights organizations would later recognize these atrocities as acts of genocide.

The Yezidi tragedy stands as a stark reminder of the lethal potential embedded in the politics of religious difference. It illustrates how theological boundary-making, when fused with militant ideology and permissive political conditions, can legitimize the extermination of entire communities. More broadly, it exemplifies the precarious existence of “liminal minorities”—groups situated neither fully inside nor outside dominant religious and political orders, whose ambiguous status renders them especially vulnerable to exclusion, displacement, and violence.

It is precisely this condition of vulnerability that Güneş Murat Tezcür interrogates in Liminal Minorities: Religious Difference and Mass Violence in Muslim Societies. The term “liminal minorities” refers to specific groups that are offshoots of the dominant religion but whose theological beliefs and cultural practices differ from those of the majority in fundamental ways. Because these groups have roots in the dominant faith tradition—but nevertheless depart from its teachings and practices—they are castigated as “deviant” or “heretical” in ways that other faiths, which do not share this genealogical connection, are not.

Drawing on an ambitious comparative framework, Tezcür examines why certain religious minorities become targets of mass violence while others do not. Through a combination of historical-comparative and quantitative analysis, he advances a compelling argument: mass violence against minorities is not the inevitable product of ancient hatreds or immutable sectarian divisions, but rather the outcome of theological beliefs that stigmatize minorities and political configurations that render liminal groups expendable. When dominant religious groups experience a loss of status during periods of political upheaval and weakened state authority, they are more likely to vent frustrations on already stigmatized, “deviant” minorities, who are perceived—often erroneously—as benefiting from the new status quo. Disturbingly, this anti-minority violence is often perpetrated not by strangers but by acquaintances and neighbors; it is rarely directed against powerful or threatening groups, but against small, stigmatized, and historically persecuted minorities.

The book is divided into five chapters. The first chapter presents Tezcür’s theory of religious liminality and its relationship to violence. The next three chapters apply this theory to four specific cases of anti-minority mass violence: Yezidis in Iraq, Alevis in Turkey, and Baha’is in Iran and Ahmadis in Pakistan and Indonesia. These rich case studies employ process tracing to demonstrate how historical liminality combined with political upheaval produces mass violence against minorities. The fifth chapter presents the results of a large-N statistical analysis examining the relationship between religious liminality and discrimination across the globe, demonstrating that liminal minorities experience significantly more societal discrimination than non-liminal groups.

In the opinion of this reviewer, Liminal Minorities represents the most important contribution to the religious persecution literature since Brian Grim and Roger Finke’s The Price of Freedom Denied: Religious Persecution and Conflict in the Twenty-First Century. The book advances the conversation on religious violence in three key ways.

First, while most scholarship focuses on intercommunal tensions between major faith traditions, Tezcür shifts attention to anti-minority violence perpetrated by dominant religious groups—a subject that has received comparatively little scholarly attention. This form of violence is particularly important because dominant groups, unlike minorities, naturally pursue grandiose objectives, such as purifying their territories of “contaminating” forces. By contrast, minorities are more likely to pursue limited goals, such as equal rights. Whereas religious violence is often portrayed as a “weapon of the weak,” Tezcür convincingly shows that it can also be a “weapon of the strong” directed against the weak.

Second, the book represents a significant rebuttal to the dominant rational-actor view of violence and terrorism, which treats such violence primarily as a strategic instrument chosen to achieve specific outcomes. Tezcür is a rare example of a political scientist who takes the content of religious belief seriously as an independent causal factor in mass violence. For him, the perceived illegitimate beliefs and immoral practices of liminal minorities foster discrimination and justify violence. Perpetrators act with a sense of divine mandate, believing that they are fulfilling God’s will through their actions.

Third, Tezcür opens important avenues for research on liminal minorities beyond Muslim-majority societies. In the Christian tradition, for example, the history of persecution against liminal minorities like Jehovah’s Witnesses, Anabaptists, and members of the Church of Jesus Christ of Latter-day Saints, as well as historical groups such as the Nestorians, Donatists, and Quakers, illustrates how theological divergence from dominant religious norms can render minorities vulnerable to persecution. The experiences of these groups suggest that Tezcür’s framework has broad applicability across religious traditions.

One question that could have been addressed more fully concerns the relative importance of liminality versus other factors in shaping vulnerability. The Islamic State, for instance, did not confine its horrific violence to the Yezidis. It also targeted Christians, rival Muslim sects, and Sunni Arabs who resisted its rule. This violence was selective but totalizing, designed to enforce ideological conformity and terrorize those who deviated from its rigid vision of Islam. Moreover, geography clearly played a role: Sinjar, the Yezidi heartland, was strategically located between Mosul and Syria, forming a corridor critical for ISIS’s military and logistical operations. Controlling this territory also allowed ISIS to dominate key supply lines and communication routes. Thus, the attempted extermination of the Yezidis can be understood as both theological and strategic. Expanding on the interplay between liminality, strategic vulnerability, and political opportunity would have further strengthened the analysis.

This minor quibble notwithstanding, Liminal Minorities is a timely and significant contribution to the literature on religious persecution. It is theoretically elegant, methodologically rigorous, and empirically rich, representing an outstanding example of sophisticated scholarship on a subject of both academic and real-world importance. Both scholars and informed lay readers will find it a compelling, insightful, and thought-provoking work.