Say “evangelical Christian,” and most people will probably think of Biblical fundamentalism, and opposition to the sexual revolution, feminism, LGBT equality, evolution, science, and secularism of all sorts. Historian Matthew Avery Sutton, however, wants you to think of something else: the End Times.

Today, fully 77 percent of U.S. evangelicals believe that we are living in the End Times, the last period before Christ returns to Earth to judge us all. That’s compared with 40 percent of Americans, and 51 percent of Protestants overall—still high numbers, when you think about it, but imagine a huge crowd at a mega-church or Christian Right political event. Three quarters of those people believe the end of the world is nigh.

Sutton’s new book, American Apocalypse: A History of Modern Evangelicalism, argues that this belief is not incidental to the evangelical movement, but central to it. Focusing on the birth of fundamentalism (roughly, the 1880s through 1940s), Sutton marshals quotation after quotation from the leaders of the movement.

For example: “We are on the brink of a world catastrophe and impending judgment,” said Billy Graham, who also asked, “Are the last days here?” way back in 1949.

Perhaps more disturbingly, Ronald Reagan said privately in 1971 that, “For the first time ever, everything is in place for the battle of Armageddon and the second coming of Christ.” One wonders if his subsequent battles with the “Evil Empire” were animated by this belief.

And the bestselling nonfiction book of the 1970s was Hal Lindsey’s The Late, Great Planet Earth, which calculated the year of the apocalypse to be—wait for it—1988.

I admit, it’s hard not to read American Apocalypse without smirking at a century of such failed prophecies. Will we ever learn?

As a longtime student of messianism, millennialism, and other end-times beliefs—I wrote my doctoral dissertation on an 18th century false messiah —I can safely say that the answer is no. Probably for deep-seated psychological reasons, human beings have always believed that it’s five minutes to midnight. Maybe it’s our fear of death. Maybe we just can’t imagine the world going on without us.

Whatever the reason, and however absurd their beliefs may seem, American evangelicals are deadly serious. And white evangelicals are today the largest American religious community, comprising 26 percent of all Americans (Catholics are second at 24 percent, mainline Protestants third at 18 percent, the African-American “black church” fourth at 7 percent). What they believe impacts economic policy, foreign policy, education policy, environmental policy, you name it.

As Sutton shows in his book, the important shift took place gradually, from the end of the Civil War until World War II. The important doctrine here is the “millennium,” which means not the period that began in the year 2000 (or 1000) but rather the thousand-long period during which Christ will reign on Earth. In the 19th century, the prevailing view among Protestants was that the Second Coming would take place after the world got better and better, paving the way for the messianic age. For this reason, it is called by scholars “postmillennialism.” I.e., millennium first, Second Coming second.

There had long been another view, however, called “premillennialism.” In this view, the world is getting worse, not better. So bad, in fact, that Christ will have to come before the millennium can get started.

Postmillennialism reigned in the progressive era, with liberal theologians advocating the social gospel and mainstream conservatives hewing to the traditional, postmillennial interpretation as well.

But in the wake of the Civil War, urbanization, immigration, and the loss of white Protestant hegemony, there soon emerged a third group: radical, premillennial evangelicals. They looked around and saw their world falling apart. And around the turn of the 20th century, they began creating a religious counterculture that preached that the End Times were upon us.

Today, liberal Protestantism is on the wane, and optimistic postmillennialism along with it. Fundamentalism—which takes its name from Lyman Stewart’s 1910 anthology The Fundamentals: A Testimony to the Truth and a derogatory sermon given in 1922 by the liberal pastor Harry Foddick entitled “Shall the Fundamentalists Win?”—has indeed prevailed. The premillenialists won.

If you think about it, though, you’ll notice a contradiction right in the heart of contemporary evangelicalism. If the world is going to end, why are evangelicals so busy trying to save it? Who cares of Barack Hussein Obama is president and gays are getting married? Don’t such events prove that evangelicals are right?

This contradiction runs throughout American Apocalypse and, indeed, the worldview of the Values Voter Summit, Sarah Palin, and George W. Bush. The best answer Sutton offers is a statement by the preacher John Roach Stratton back in 1918. Said Stratton, “The supreme duty of the church today is not to patch up and paint a wrecked world but to get out the lifeboats and take as many souls as possible off the wreck.”

Jesus saves—not just from hell and damnation, but the impending apocalypse, which is about to engulf the world. That’s why you need to get born again. Because otherwise you will be left behind.

Relatively few evangelicals are strict dispensationalists, believing that there’s nothing you can do to escape your fate. Most believe that there’s still time to save yourself from the chaos that is to come—and they’re going to make sure you know it. Each gay man who stays in the closet and marries, each woman who carries her baby to term is one more soul saved from the end of the world, which is just around the corner.

I wonder, though, if this causality is backwards.

As Sutton shows, premillenialism came as a response to massive social changes: urbanization, industrialization, the Civil War, and the rise of American Catholicism. Today’s changes are different: the sexual revolution and a majority-nonwhite America. But the enduring response—stop the world, I want to get off—is the same.

Those people petitioning for “religious freedom” aren’t opting out of civil rights laws. They’re opting out of a world they believe to be literally going to hell.

And more than that—the world is ending because of the changes that many of us see as positive. Think about it: three-quarters of white evangelicals believe that I’m going to be engulfed by the wars of the Antichrist, and in a way, I brought it on myself, with all that sex and beer and women voting in elections.

For premillenial evangelicals, it really is the end of the world as they know it—and as long as the deserving ones get raptured, they feel fine.