Andrew Preston was a lecturer in the History Department at Yale in 2002 – 2003 teaching courses on US diplomatic history when he observed the extensive use of religious language by President George W. Bush in his State of the Union address, and in other settings, in relation to the pending U.S. invasion of Iraq. Although Preston and his students had studied the United States’ role in many conflicts and regions, including the Cold War, Cuba, Chile, Vietnam, and the war on terror, what they were most perplexed by was the use of religious language and images by President George W. Bush to frame intervention in Iraq which seemed dramatically different from other administrations. Preston asked the question: “Is the use of religious rhetoric to justify foreign policy normal for presidential administrations, or was it something new with Bush?” Thus, this book is Preston’s quest to discover more about the role of religion in American foreign policy.
 On further examination, Preston discovered that very few in the community of diplomatic historians had considered the role of religion as a factor in shaping American foreign policy. Likewise, when he looked into the realm of religious historians, there was also a dearth of studies and discussions of the role of religion in diplomacy and foreign policy.
 “The problem, at least for me” he says, “was that historians of religion were interested in religious issues; their discussions of, say, World War I did not intend to shed light on the war, but on how religion reacted to or was changed by the war. In the same way, historians of American foreign policy were not especially interested in religious issues. Sporadic references to the other abounded in each discipline, but only a rare few scholars integrated them in a sustained and meaningful fashion. Yet there were obvious historical moments when the two subjects would have had to meet in interesting and revealing ways.” (Preface)
 One of Preston’s immediate discoveries about the American population is that we are a nation of immigrants with roots in other countries, leading us to naturally transcend national boundaries. Immigrants, says Preston, often thought of themselves as citizens of the world. “While religious faith helped create an American nationalism, it also fostered a powerful sense of internationalism.” (P. 4)
 Preston’s book is a study of how religion shaped America’s engagement with the wider world – not just the use of diplomatic and military power, but also the efforts of private citizens, missionaries, and other nongovernmental organizations. Religious faith, which infused the American population, played a significant role in mobilizing citizens to engage the world, to organize around international concerns, and often to directly appeal to the power structures of Congress and the White House. In some cases, religious values played a direct role in the formulation of policy in Congress. Religious values also inspired open resistance to US foreign policy initiatives.
 Religion, argues Preston, has been largely ignored in the discussion of foreign affairs, even as it plays such a significant role in lives of the American people, and has been an element in the arena of US foreign affairs. Preston covers the broad sweep of American history from the early revolutionary period, addressing the influence of religion in most presidential administrations, to the recent years of George W. Bush and Barack Obama. He does not intend to create another master foreign affairs narrative, but to show the missing link, the influence of religion on foreign policy and foreign affairs. Two broad categories are reflected in the book’s title: sword of the spirit and shield of faith. Sword of the spirit, from St. Paul’s instructions to the Ephesians, often meant waging war in the name of God, for Americans. The shield of faith, also part of St. Paul’s instructions, has been less recognized. In American history it has led people of faith “to the promotion of peace: Christian pacifism, anti-interventionism, anti-imperialism, and internationalism.” (P. 7 – 9)
 Preston offers three reasons why it is impossible to overlook the dimension of faith in consideration of foreign policy and international relations. First, it mattered to individuals who were in positions of power and influence. More than simply a public piety, the sentiments and convictions behind the proclamations and policy options of leaders such as Presidents Franklin Roosevelt and William McKinley and Secretary of State John Foster Dulles, reflected a personal religious biography that was largely ignored.
 Secondly, despite the major shortcomings and imperfections of the developing democracy, including slavery, the genocidal treatment of Native Americans, and the lack of franchise for women, political and diplomatic elites were compelled to listen to the voices of the people. The U.S. was becoming a mass democracy and popular opinion could not be ignored.
 The third reason for paying attention to religion in foreign policy and international affairs reflected the place of the US in the world. It was a relatively new state compared to others in the international system, and it had the status of free security. The US was bordered by two vast oceans, not by other countries that immediately threatened its security. From 1815 to 1941 the U.S. was relatively free to develop its political culture and foreign policy separate from the immediate demands of national security concerns.
 Using numerous instances, especially with U.S. presidents and key members of Congress, Preston corrects the failure to include religious biography of influential individuals and the role that faith played in their perspective on international affairs and foreign policy decisions. For example, Preston identifies William McKinley (pres. 1887- 1901) as one of the most pious U.S. presidents to ever hold the office. This pro-business Republican from Ohio took a variety of progressive actions as the result of the influence of his evangelical Methodist faith, including opposing Jim Crow practices, representing labor unions, and supporting the temperance movement. The decision to go to war with Spain and eventually annex the Philippines was heavily influenced by McKinley’s religious convictions. In a quandary over what to do with the Philippines following the defeat of Spain, President McKinley acknowledged to a church missionary committee that getting no help from either Republicans or Democrats, he finally fell to his knees in the White House and sought divine guidance. A day or so later he realized that “there was nothing left for us to do but to take them all, and to educate the Filipinos, and uplift and civilize and Christianize them, and by God’s grace do the very best we could by them, as our fellow-men for whom Christ also died.” (p. 156)
 Another example of the importance of religious biography is seen in the person of Alfred Thayer Mahan, at the Naval War College in Rhode Island, considered the top naval strategist of the late 19th century. His advice was heavily sought after by kings, queens, presidents and prime ministers. Mahan’s doctrine of “the influence of sea power upon history” argued that great power status depended heavily, if not exclusively, upon the ability to command the seas. (p. 208) Underneath this grand security strategy was the deeply held conviction that Christianity was the source of civilization. His faith convictions were so prominent that a missionary school in China was designated the Mahan School in his honor. Christian faith for Mahan was the basis for “progress, justice, and liberty” and it touched upon such things as the status of women and the administration of justice. The simple truth for him and for engaging the world was that “God rules all.” (p. 209)
 Preston offers numerous examples of how “the Sword of the Spirit” impacts the formulation and exercise of U.S. foreign policy as the Christian faith was often part of the rationale for waging war. God was understood as sanctifying the march to war. “The Shield of Faith,” expressed as opposition to war, also has a rich history, most notably in the Cold War, following two major crises that brought the US and the Soviet Union to the brink of nuclear war: construction of the Berlin wall by the Soviets in 1961 and the Cuban Missile Crisis in 1963. During this period the National Council of Churches initiated a series of cultural and religious exchanges between the US and the Soviet Union, an effort designed to lead by example by furnishing “practical examples of their own national and international affairs” as the Reverend Stewart Herman (the first president of LSTC) told a Soviet – American religious leaders audience at the Episcopal Seabury House in Greenwich, CT. (p. 497)
 An especially inspiring example of religious values at work in the U.S. Congress is the fight in the early 1970s in defense of Russian Jews and their right to practice their faith in the Soviet Union, which eventually expanded to include Roman Catholics in Ukraine, Lutherans in the Baltic States, the Russian Orthodox Church and Soviet Protestants. Key leaders in this movement who stood at odds with the White House, and Henry Kissinger, who did not want to threaten the new era of Détente included: Robert F. Drinan, the Jesuit priest, law professor, and member of Congress from Boston; Henry M. “Scoop” Jackson, Lutheran from Washington state; Jacob Javits, Jewish from New York; and Charles Vanik, from Ohio. For these members of Congress, this was a basic matter of human rights to which they applied their religious values.
 Sword of the Spirit, Shield of Faith delves into the rich history and complexities of U.S. foreign policy and diplomatic relations. It also offers a glimpse of the history of the social teachings of the American Christian church, including the conflicts and differences that developed, and continue, between the more conservative, often fundamentalist expressions of Christianity, and the mainline expressions of historic Protestantism, and Roman Catholicism. Preston also discusses points where organized Judaism enters the foreign affairs fray.
 This book has much to offer for anyone interested in the role that religion has played in international affairs and the formulation of foreign policy. Two people who show up repeatedly in the 20th century are Reinhold Niebuhr and his use of Christian realism, and the diplomat and international relations expert George Kennan who was grounded in Calvinism. Preston concludes where he started, with a more detailed analysis of the religious influence on the foreign policy of George W. Bush, followed by a brief excursion into the views of President Barack Obama who has been influenced by the thinking of Reinhold Niebuhr.
 Despite his extensive overview, Preston appears to have missed the importance of several key events. There is no mention of Bread for the World, the largest, most active Christian-based education and global hunger advocacy organization, which engages in serious legislative advocacy. While he gives some attention to early Christian Zionism, especially around the time of the Balfour Declaration, Preston never mentions it again, thus overlooking the role of organizations such as Christians United for Israel which has a huge influence on Capitol Hill in support of Israel. Neither does he discuss the religious significance of the Israeli – Palestinian conflict where the US is heavily invested. He also mentions only briefly the role of the Presbyterian and Reformed traditions, Yale Divinity School and Andover Newton Seminary in the establishment of the Syrian Protestant College which became the American University in Beirut, a major Christian effort to infuse Christian and Western values into the culture and life of the Middle East. Likewise, he does not mention the American University in Cairo which has a similar history and purpose. Finally, Preston gives minuscule attention to the role of the church in opposing Apartheid in South Africa, and he says nothing about American Lutheran opposition to the South African occupation of Southwest Africa and their contribution to creating the nation-state of Namibia.