Once upon a time, religion and the state were everywhere inseparable. How did that change? Why did religion get removed as the state’s justification for its own laws and for its subjects’ rights in some places but not others? And in places where the state remains religiously defined and legitimized to the present day—think of Iran, where women have recently erupted in revolutionary protest over the many religiously inspired restrictions the state imposes on them—what are the prospects that citizens might someday win, not freedom of religion, but freedom from religion?

These are the puzzles of “institutional secularization” that motivate H. Zeynep Bulutgil’s tremendous new work of comparative political history. Before detailing her arguments and evidence—which, to foreshadow, prove deeply compelling—it is worth pausing and reflecting on just how substantial the historical puzzle of state secularization truly is. What Bulutgil rightly establishes as the “historical baseline” (pp. 19-20) of institutional fusion between religion and state could simply have lasted everywhere. Religious organizations enjoyed enormous initial advantages over any fledgling secular rivals, and the state was firmly on their side. The answer to how and why institutional secularization has been achieved anywhere at all thus requires an answer to how and why this cavernous secular disadvantage has, at least in some times and places, been overcome.

Bulutgil’s argument for how and why unfolds in two stages. First, the rise of print-capitalism and the relaxing of censorship allowed secular ideas to spread and secularizing movements to emerge. This did not happen everywhere; indeed, it has still not happened everywhere. Those secularizing political movements then became pivotal at stage two. Where they could tap into strong civil-society organizations and—most vitally of all—where they preceded and gained a historical head start on their religious party competitors, secularizing movements could win power and remove religion from state institutions for good. France and Turkey are Bulutgil’s primary examples of where this occurred most decisively. Spain and Morocco are her main cases where religion’s chokehold on the state has proven far tighter. Finally, the United Kingdom and Tunisia provide intermediate cases, where secularizing political movements removed religion more successfully than in Spain and Morocco, but less thoroughly than in France and Turkey.

The case selection is thus a model example of a controlled historical comparison. And it is firmly nested in Bulutgil’s cross-national quantitative analysis, which sets the stage for the rich historical process-tracing exercises that follow. By comparing a variety of variables at their highest and lowest values, Bulutgil generates a litany of substantively important results. She finds that printing houses make the rise of secularizing parties nine times more likely, and censorship makes it three times less likely. The existence of a secularizing party makes institutional secularization seven times more likely. Most striking and significant of all is Bulutgil’s finding on the relative timing of secular versus religious parties. Where secular parties gained the biggest early-mover advantage, institutional secularization was eleven times more likely than where they emerged latest, or not at all. All of these results compare favorably to basic modernization theory: higher GDP per capita makes institutional secularization only twice as likely. As is so often the case, modernization matters, but it is not what matters most.

Bulutgil shows us what does. Her book’s subtitle captures it succinctly: ideas, timing, and organization. But it is the middle factor, timing, that looms largest both for its theoretical novelty and its empirical impact. The first stage of her argument is essentially a mashup of theoretical giants: Benedict Anderson and Jürgen Habermas. The rise of secular ideas and secular organizations was key in the triumph of secular institutions. Yet what Bulutgil portrays as theoretically nearly necessary is far from empirically sufficient. In 43% of her country-year observations, the prior emergence of a secularizing party failed to give rise to a secularized state (p. 54).

Here enters timing, and time itself. Most simply rendered, Bulutgil’s big theoretical claim is that secular movements can reshape the state when they emerge before their religious rivals and have had ample time to build organizational strength. An attractive element of this claim is that it can help explain more than just secularization. For instance, organizational first-mover advantages dating back to the nineteenth century go a long way toward explaining why the military played such a leading role in Turkish political development and why the monarchy continues to dominate politics in Morocco.

As with any excellent political history, the empirical chapters contain way more insights and lessons than any basic theoretical flowchart can channel. Although organizations ostensibly only enter Bulutgil’s argument at stage two, the case studies are loaded with organizational analysis at stage one. It is not print-capitalism and lightened censorship that opens her narratives, but patterns of state-building that led to more extensive elite diversification and associational development in some cases than in others. Military academies, universities, and secret societies infuse the histories and motor the politics. It is not only the relative strength of secular and religious forces, but their patterns of internal division and cohesion that determine how their historical collisions and contestations play out. And it is not only Bulutgil’s key variables that explain higher overall levels of secularization in her three European cases than in her three Middle Eastern cases. Fascinatingly, it was the rift between religion and republicanism wrought by the French Revolution and its aftermath that made religious actors slow to shift from pure monarchical defense to active party politics. From this perspective, Europe’s secular advantage was not so much about the impressive socioeconomic modernization of its secularist forces as the remarkable political sluggishness of its leading religious actors.

Herein lies my only mild critique of The Origins of Secular Institutions, which really signals a broader challenge to all works of comparative historical analysis in political science. Blending an elegant theory with rich comparative case narratives will never be easy. In Bulutgil’s approach, the theory and the narratives are more segregated than integrated. The introductory theoretical chapters make virtually no reference to the cases that ultimately animate that theory: proper names are eliminated all too well. And the empirical chapters make only uneven and occasional references back to the key theoretical concepts from the introduction, proceeding mostly by chronology, especially in the three European cases. All in all, the Middle Eastern cases make the more gripping, disciplined, and informative reads. It is almost like reading two separate books, one theoretical and one empirical, rather than one.

Both halves of Bulutgil’s marvelous analysis culminate in the same big concluding question. If institutional secularization requires that secular movements enjoy the time and space necessary to overcome their organizational disadvantages vis-à-vis the church, mosque, and temple, will freedom from religion ever be won in places that still lack it? How can secularism be secured in the twenty-first century? Perhaps some hope rests in the fact that secularism may be granted rather than seized; if secular politicians sometimes meddle with religion to build wider political coalitions, maybe sometimes religious politicians can experiment with secularization to do likewise. But Bulutgil’s big lesson is that secularization typically needs secular movements to seize it. So watch Iran, and watch the world, keeping Bulutgil’s marvelous book close at hand as you do.