Mark Massoud's extraordinary new book is both an argument about the rule of law, based on a careful study of the relationships between law, religion and politics in the Horn of Africa from the 1880s to 2020, and a performance of that argument.

The book's argument about the rule of law is that the liberal democratic principles that are associated with this ideal – from limited government to protection of human rights – are not necessarily opposed to religious principles such as those associated with shari‘a. Rather, these rule-of-law principles may be entirely compatible with, complementary to, and even indistinguishable from the religious principles. In Massoud's account, shari‘a, like state laws and the idea of the rule of law, is radically indeterminate, leaving it open to diverse and even contradictory interpretations, practices, and thus politics. The book's intervention here is to show how, across a century and a half of Somali politics, both law and religion have been deployed in ways that have set shari‘a against the rule of law, but that have also made shari‘a the basis of the rule of law, or at least its hope. For those who hold the view that shari‘a (or religion more generally) and the rule of law are fundamentally incompatible – and those would be the majority of actors from the Global North engaged in international development – this book will make it very hard to maintain that view.

And that is the book's primary audience: a ‘law and development’ orthodoxy, situated largely in the Global North (and above all in the USA), who study and work to institute ‘the rule of law’ through state-building and development projects largely in the Global South (and above all in Africa). The book is framed in a way that speaks to this audience, but it does so through a subtle performance of its own argument. If this is a book about how law and religion can be used strategically to advance diverse and often opposed political agendas – that is, if it is about how law and religion are used as a means to political ends, which Massoud terms legal and religious politics – then the book is also itself a carefully crafted work of legal and religious politics. Shari‘a, Inshallah is an intervention that advances a liberal democratic rule-of-law orthodoxy by reinterpreting it in a way that makes it not just compatible with, but indistinguishable from, the rule of religion – and not just any religion, but the religion that has (re)emerged in an Anglo-European imagination as the gravest threat to a ‘Civilised’ liberal democratic state based on the rule of law: Islam.

And yet, as a reader who is deeply critical of the work of international development, and who has no difficulty imagining a rule of law that is the rule of shari‘a, I found the book's overarching argument and intervention to be less interesting and important than its underlying ‘case studies’. In between the two framing chapters on the rule of law (Chapter 1 and Chapter 7), the book undertakes a careful study of the intertwined uses of law and religion to support and contest state-building efforts during British and Italian colonisation of the region from the 1880s to the Second World War (Chapter 2); during Somalia's period of independence and unity from 1960 to the civil war of the 1980s (Chapter 3); and during the fragmented period from 1991 to the present in Somalia (Chapter 4) and in the self-declared state of Somaliland (Chapter 5 and Chapter 6). The result is an expansive yet deeply researched account of a dynamic legal and religious pluralism in the Horn of Africa, which is beautifully written, and written as far as possible from Somali perspectives, based on extensive fieldwork in the region as well as archival research. Immersed in the struggles of Somali legal and religious politics, one could – and I did – forget that they have anything to do with the framing liberal democratic concern for ‘development and the rule of law’. The reminder is there, of course, in the insistent international interventions carried out in its name. But one of the achievements of Massoud's work is to not allow that (Western) focus to dominate, despite the book's own framing. This is a book on Somali politics, which foregrounds the ways in which state and non-state actors – including sheikhs, sultans, aqils, elders, lawyers and feminist activists (who get a dedicated ‘case study’ in Chapter 6) – have used law and religion in their efforts to create the conditions within which their communities can live and flourish, against a background of ongoing imperial intervention. This is an exemplary work of contemporary legal anthropology that makes an outstanding contribution to the fields of ‘law and (post)colonialism’ and ‘law and development’, to the study of ‘legal pluralism’, and above all to a thick understanding of the complex relationships between law and religion, through a sensitive Somali-oriented examination of legal and religious politics in the Horn of Africa.