Religion is the key to history, Lord Acton wrote. In today’s intellectual circles, however, it’s more like the skunk at the garden party. To many intellectuals, religion is a private matter at best, and most appropriately considered in terms of its functions rather than the significance of its beliefs, let alone its truth claims. At worst, it’s the main source of the world’s conflicts and violence—what Gore Vidal, in his Lowell Lecture at Harvard University in 1992, called “the great unmentionable evil” at the heart of our culture.

Such grim assessments are certainly debatable. It’s a simple fact, for example, that, contrary to the current scapegoating of religion, more people were slaughtered during the 20th century under secularist regimes, led by secularist intellectuals, and in the name of secularist ideologies, than in all the religious persecutions in Western history. But there is little point in bandying about charges and countercharges. If we hope to transcend the seemingly endless culture-warring over religion, we need detailed, objective data about the state of religion in today’s world, and wise, dispassionate discussion of what this evidence means for our common life.

Is religion central or peripheral? Is it disappearing, as Auguste Comte, Karl Marx, Friedrich Nietzsche, Max Weber, Émile Durkheim, Sigmund Freud, and other proponents of the strong secularization thesis have claimed? Or is religion actually resurgent, as more recent observers such as Peter Berger, David Martin, Rodney Stark, and Philip Jenkins have claimed? Is it a positive force, as some have argued from the evidence of the “South African miracle,” the peaceful transition from apartheid to equality? Or is it pathological, as much of the post-9/11 commentary has assumed without argument?

In their new book, political scientists Pippa Norris, of Harvard, and Ronald Inglehart, of the University of Michigan, contribute three things to the old debate: first, a summary of the present state of academic analysis of religion; second, new evidence on the state of religion in the modern world; and third, a new theoretical framework that they claim makes better sense of the evidence than previous theories.

The massive and detailed evidence of religion’s significance worldwide is unquestionably the chief benefit of the book, helpful even for those who will disagree with the authors’ conclusions. The data come from World Values Surveys, an international cooperative overseen by Inglehart, for which social scientists polled residents of more than 80 countries  between 1981 and 2001. The findings cover a comprehensive sweep of topics, ranging from the personal importance of religion to the electoral strength of religious parties in national elections.

The weight of all the data, interestingly, points somewhere between the extremes of the debate. Religion is far from dead, and it certainly hasn’t disappeared—even in Europe, where the evidence for its demise is most powerful. But there is strong evidence that it has lost its decisive authority over the lives of adherents in the developed world—even in the United States, where American exceptionalism has long defied European trends toward secularization. There was certainly too much of an unacknowledged secularist bias in secularization theory, but at the same time much of the talk of the unabashed resurgence of religion is premature. For those who take faith seriously, the general trends in the modern world are sobering; the still-potent role of religion in the global south offers only false comfort, as most of the region is still premodern and has yet to go through the “fiery brook” of modernity.

Norris and Inglehart’s theoretical explanation of religion’s current condition will be more controversial: a revised version of the secularization thesis, which they base on the “existential security” offered by religion. In contrast to Weber’s view of modernization as “rationalization,” or Durkheim’s as “differentiation,” they trace the growing irrelevance of religion in the modern world to the fact that people can take security for granted. The more secure people become in the developed world, the more they loosen their hold on religion; religion, meanwhile, retains its authority among the less secure but faster-growing populations of the less developed world. “The result of these combined trends,” the authors conclude, “is that rich societies are becoming more secular but the world as a whole is becoming more religious.”

The main response to this theory will properly come from Norris and Inglehart’s fellow scholars, and is likely to focus on three aspects: the authors’ interpretation of the data they offer, their critiques of some of the currently flourishing theories, and their view of secularization as driven by the accrual of “existential security.” Their articulation of the last seems to me particularly disappointing, little more than a restatement of Lucretius’s “Fear made the gods,” and a crude explanation for the crisis of religion, which could be explained as easily by Aleksandr Solzhenitsyn’s simple observation, “Men have forgotten God.”

What really ought to be addressed, however, are the implications of Norris and Inglehart’s findings for the Western democracies. They nowhere discuss religion as having more than a generic, functional role in assuring existential security. Such a view is inadequate for those who take the specific content of faith seriously, and who argue that faiths of a certain shape produce citizens of a certain shape, who in turn produce societies of a certain shape—in other words, that faith must be considered as a set of beliefs with particular consequences and not others. Weber’s magisterial work led the way in this direction, and Baylor University sociologist Rodney Stark’s important work on monotheism adds to it currently.

The condition of religion in the modern world is especially crucial to a society that links religion and public life in any way—and nowhere more crucial than in the United States. Religion in America has flourished not so much in spite of the separation of church and state as because of it. Far from setting up “Christian America,” or establishing any orthodoxy, religious or secular, the Framers envisioned the relationship of faith and freedom in what might be called a golden triangle: Freedom requires virtue, virtue requires faith (of some sort), and faith requires freedom. If the Framers were right, then as faiths go, so goes freedom—and so goes the Republic.

America has yet to experience the discussion of religion in 21st-century national life that “the great experiment” requires and deserves, not just from scholars but from a host of Americans—schoolteachers and political leaders alike. Norris and Inglehart provide data and arguments that will be an invaluable part of that discussion.