"[F]or our sakes who adore Thee, Lord, blast their hopes, blight their lives, protract their bitter pilgrimage, make heavy their steps, water their way with their tears, stain the white snow with the blood of their wounded feet! We ask it, in the spirit of love, of Him Who is the Source of Love, and Who is ever-faithful refuge and friend of all that are sore beset and seek His aid with humble and contrite hearts. Amen."

-Mark Twain, the War Prayer

To Andrew Preston, it is not a question of whether or not religion has had an influence on American foreign policy, but instead how much, and by what means it has done so. Religion and religious identity remain an indelible stamp of the United States' distant origins which cannot so easily be removed. Its awakening was in the earliest ages of American colonialism - John Winthop's vision of a city on the hill, stodgy Puritans in fierce wars with the natives, and so forth. This is only the beginning, however, as Preston traces overt religious backing, or at least some religious influence or allusion, in a long thread stretching through The Revolutionary War, western expansion, the long bloody fields of Manifest Destiny, the Civil War, the Spanish-American War, and the 'Christianization' of the already Catholic Philippines, Wilsonian liberal internationalism, and even the Second World War, Communism, the 'cowboy crusades' of Bush II, and Obama's tough application of the political theologian Reinhold Niebuhr.

The story of religion in America is largely influenced by the story of Protestantism - independent and non-hierarchical - for better and for worse. Catholicism and Judaism play greater roles in the 19th and 20th century, and then alternate religions and atheism begin to make the smallest of headway in the 20th and 21st.

Although religion is often very eager to lend its voice to justify war, there is also a long pacifist/human rights tendency in it as well - The World Wars and the Cold War are a major example of this. Abolition, of course, drew from Christianity. Missionaries in the 19th century helped to spread an image of a sort of Democratic Peace. Roosevelt in the 1940s led a savvy and confident leadership against the evils of totalitarians, using subtle allusions to religious rhetoric. Carter was a profoundly religious man who focused on human rights, although had difficulties with their application.

The chief peculiarity of the United States, as a Christian hegemonic republic, instead of being another Christian Empire of the Middle Ages, is at least a nominal tolerance of the faiths of others, and the ability to practice them. Although whether religion, for better and for worse, will continue to exist in its present form as a shared language and set of common ideas among policymakers and citizens, yet remains to be seen.

A deeply-researched book, on a topic with broad and far-reaching implications. ( )