Sword of the Spirit, Shield of Faith

British academic Andrew Preston offers a crisply written account of the historic intersection of religion and US foreign policy.

In the fall of 1898, President William McKinley faced a dilemma. America's "splendid little war" had put an end to Spain's colonial rule in Cuba, Puerto Rico, Guam, and the Philippines. He knew that Puerto Rico and Guam would become US protectorates and Cuba nominally independent, but the fate of the Philippines remained a puzzle. Dissatisfied with the advice he received from both Republicans and Democrats, he turned to God. As McKinley told the story: "I walked the floor of White House night after night until midnight; and I am not ashamed to tell you, gentlemen, that I went down on my hands and knees and prayed to Almighty God for light and guidance more than one night." Finally he had the answer: The United States would lay claim to the Philippines.

McKinley's faith helped him to resolve a foreign policy dilemma – and he's not the only president or politician to draw on religion when confronted with a diplomatic crisis or conundrum. Woodrow Wilson's vision for a new world order was grounded in the Christian principles of fellowship and love, tenets he learned in the Calvinist household of his youth. Harry Truman believed that American society could not function without the clear definitions of right and wrong that religion provided. His Baptist faith, along with the need to court the Jewish vote, led to US support for the establishment of Israel, against the advice of the State Department.

Historians of American foreign relations have been traditionally leery – and sometimes dismissive – of the notion that faith plays a serious role in these moments of decision. The intangible, personal nature of religion makes it hard to square with more realist considerations like troop numbers, nuclear capacity, and trade imbalances. But ignoring religion means excluding a vibrant aspect of American culture and denying that policymakers have spiritual lives. Over the past decade, historians have studied the intersection between religion and American diplomacy by looking at everything from missionaries as proselytizers of American values to campaigns for religious liberty abroad.

Now comes Andrew Preston, senior lecturer in American history at Cambridge University, with Sword of the Spirit, Shield of Faith: Religion in American War and Diplomacy. Preston argues that religion has significantly shaped American foreign relations from the Puritans  onward. It's the first book to comprehensively tackle the subject, a crisply written account hefty in both scope and intellect. As Preston takes on the challenge of explaining in tandem the evolution of America's religious culture and its foreign policy – each an intellectually dense topic in and of itself – his book buzzes with the resulting frisson.

Preston argues that the core features of religion's influence on American foreign relations developed early. All of the Founders were grounded in the teachings of the Bible and the Protestant faith. While they embraced a religious worldview to different degrees, they all believed that faith and modernity were complementary forces and religion had a constructive role to play in American culture. For them, religious liberty and democracy went hand in hand. The merging of revolution and religion also forged three principles that had long-term influence on American foreign policy: unilateralism, republicanism, and separatism.

Between 1815 and 1941, American foreign policy developed largely independent from the pressures that plagued countries in Europe and Asia. Because the United States didn't have to be concerned about physical security – Canada and Mexico weren't in a position to mount an invasion – politicians and religious groups could push for policies that were based on moral principles rather than security. The pluralistic nature of American religion helped foster political movements, such as abolition, Progressivism, and Prohibition. These same reforming impulses found expression in an American foreign policy that pursued human rights, the promotion of democracy, and humanitarian intervention. At the same time, politicians used religious idealism to rationalize their actions. McKinley justified, in part, the United States becoming an imperialist power in the Philippines by the need to "uplift and Christianize them," completely ignoring the fact that the country was 90 percent Catholic.

World War II ushered in a new civic religion as Protestant values were replaced by a Judeo-Christian outlook that "celebrated religious liberty not only as a source of political freedom, but also as source of tolerance." In October 1941, Roosevelt warned the American public that Hitler planned to abolish all religions, telling his audience, "The god of Blood and Iron will take the place of God of Love and Mercy." American churches rallied around the war effort, combining faith with patriotism, only to doubt its morality in the wake of Hiroshima and Nagasaki.

Preston notes that during the Cold War, the same conditions that gave espionage and propaganda a heightened role – the lack of direct military engagement – also boosted religion's place in American foreign policy. Christianity was held up as an antidote to godless communism and the promotion of religious freedom was seen as a means to chip away at the monolith. Truman regularly used biblical allusions to sell his policy of containing the Soviets. In contrast, the Kennedy and Johnson administrations were downright hostile toward the merger of religion and foreign policy, particularly when religion came in the guise of criticism. Conservative religious groups derided any policy move that could be perceived as soft on communism, while liberal sects offered sustained critiques against the Vietnam War and the expansion of America's nuclear arsenal. Reagan teamed up with the Religious Right to wage his rekindled rhetorical assault on the Soviet Union.

Preston works hard to steer a middle course, explaining the development and evolution of religious beliefs and faith-based initiatives without passing judgment. It's a difficult balance to maintain, but the evenhandedness allows readers to play Solomon and reach their own conclusions. It also means that those who believe religion should play a role in foreign policy will find plenty of examples to make their case – as will those who prefer that a demilitarized zone exist between Church and State.

Because of the size of the book, Preston has broken the narrative into sections. That's perfect for people who want to focus on a particular era or just dip in and out, but if you read straight through, the short introductions to each section become maddening. They interrupt the book's chronological flow and argumentative momentum by zipping ahead and back. I could also chide Preston for ignoring the interwar disarmament conferences and spending too long on John Foster Dulles, or wish that the Civil War section wasn't so diffuse. But these are minor complaints when measured against the overall achievement of the book. Preston has crafted a work that will define the field for a generation to come. Nobody who writes about religion and American foreign policy will be able to do so without engaging him. And anybody who wants to understand American foreign policy – both then and now – would be wise to do so, too.

Meredith Hindley is a historian living in Washington, D.C. She is a senior writer for Humanities, the magazine of the National Endowment for the Humanities, and her work also appears in Salon, Lapham's Quarterly, and The New York Times.

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