The last paragraphs of American Crusaders may be the strangest of the entire book, but also the most revealing. Jon P. DePriest voices an impassioned plea to evangelical Protestants to avoid mixing religion and politics. To do so, he invokes, of all people, Harry Emerson Fosdick, the avatar of Protestant modernism during the 1920s, a tradition known more for the Social Gospel and disdaining fundamentalists than for distinguishing the sacred from the secular. Even odder in DePriest's selection of a Fosdick quotation is the Riverside Church pastor's repudiation of modernism (or adjusting Christianity to modernity) as foolish. To recalibrate the faith to modern science was one thing, but to adjust to contemporary nationalism, imperialism, capitalism, and radicalism was to sink and submerge religion “in undifferentiated identity with this world.” In other words, according to Fosdick, “harmonizing slips easily into compromising” (308).
In the spirit of a Protestant modernist, DePriest appeals to evangelicals to “purify faith through the separation of religion from political polarization.” He adds: “All evangelicals have muddied these waters.” The task for born-again Protestants is to “open up the well for all who will call upon Christ as Savior and drink of the living water” (308).
To end a history of evangelicalism and U.S. foreign policy with the equivalent of an altar call is awkward enough. But to appeal to a Protestant who became famous for fusing religion and politics to implore evangelicals to avoid such mixture is well-nigh disorienting. As accurate as DePriest's narrative of American foreign policy is, and as widely as the author has read in the historiography, the analytic categories used and explanations offered fail to yield either a coherent indictment of evangelicalism or a plausible interpretation of Protestantism's influence on American foreign policy. The book gives the impression that evangelical Protestantism is largely responsible for notions of American exceptionalism (the idea that the United States has unique gifts to render incomparable service to the entire world). But DePriest does not attempt to define evangelicalism as the beliefs of a segment of the American population, nor does he organize his material in a way that features evangelical influence at specific decisive moments in the nation's intervention in world affairs.
The book is lengthy, owing partly to its scope—all of U.S. history—and to the material in which American Protestants and federal officials have attributed religious significance to the United States. DePriest might have started with America's War for Independence and the War of 1812 as the opening chapter in the nation's foreign policy. But he cannot resist colonial developments that planted the seeds of a “city on a hill” in the soil of the American founding. By the mid-nineteenth century, which the first section covers, when Manifest Destiny inspired America's expansion across the continent, according to DePriest, “the pursuit of God's Kingdom and the pursuit of the ideal governmental system” fused into a national mission of “crusading for God” (xx). The second part of the book follows these twin ideals into the period of wars—from the Spanish American to World War II—when the United States became a global power and did so with a pronounced self-righteousness. The Cold War dominates the last section in which religious nationalism energized the contest with godless Communism. Throughout the book, DePriest weaves U.S. foreign policy and American Protestantism.
Because foreign policy and religious history have their own interpretive challenges, DePriest struggles to correlate them into a recognizable pattern. Of course, the nation and its presidents, foreign policy officers, and pastors have resorted to Christian idealism to justify America's conduct in the world. The degree to which this appeal was made at a given time is often rhetorical—to attribute higher meaning to ordinary (if not nefarious) affairs is a question that DePriest does not ask. Nor does he sort out differences between civil religion and Christian nationalism. He even fails to capture the diversity of American Protestantism. The book alleges to be a history of the way “people of evangelical faith have orchestrated a significant part of American foreign policy” (xviii). But despite a section on the modernist-fundamentalist controversy and the fracturing of the Anglo-American denominations in the 1920s, DePriest treats the influence of Protestantism on foreign policy as if it comes exclusively from evangelicals. This forces John Foster Dulles, Secretary of State under President Dwight Eisenhower, into being a spiritual descendent of Jonathan Edwards, when in fact the diplomat had no ties with evangelicalism but was a liberal Protestant.
Such mischaracterizations do not mean that DePriest is wrong to fault evangelical Protestantism for failures in American foreign policy. As much as mainline Protestantism did inform the nation's self-understanding at least until 1970, since Ronald Reagan's election, born-again Protestants have kept alive older white Protestant notions about American exceptionalism. DePriest's desire to reveal the errors and dangers of Christian nationalism is wholesome. But it does position his book more as theological critique for believers than a monograph for scholars. The author's lack of conceptual precision, combined with such a vast topic, results in a survey of American foreign policy and what Protestants thought about it, with moral exhortation mixed in. American Crusaders could be useful for pious beginners. But in the field of religion and U.S. foreign policy, it will not displace Andrew Preston's Sword of the Spirit, Shield of Faith: Religion in American War and Diplomacy (A. A. Knopf, 2012), Walter A. McDougall's The Tragedy of U.S. Foreign Policy: How America's Civil Religion Betrayed National Interest (Yale University Press, 2016), and William Inboden's Religion and American Foreign Policy, 1945–1960: The Soul of Containment (Cambridge University Press, 2008).
