My college recently started its Center for Military History and Strategy. We’ve been able to bring in some of the best historians whose work intersects military history, the Classics, philosophy, and religion. I’m a trained historian of the United States, and spent a good part of my undergraduate and graduate years reading military history, in particular the history of the American Civil War. I did not think that much about the intersection of military and religious history, but the historiography of the US Civil War is expansive enough to include works like Harry Stouts Upon the Altar of A Nation, George Rable’s God’s Almost Chosen People, Steven Woodworth’s While God is Marching On, Mark Noll’s The Civil War as a Theological Crisis, Robert Miller’s Both Prayed to the Same God, and other fine books on the topic.
My own research is on the Early American republic, which I’ll broadly define as the period between 1789 and 1861. I set out to research how early American soldiers conceived of the connection between military service, and warmaking, and their Christian practice, and also how American clerics articulated Christianity’s interactions with war. A quick Google search—hardly the definitive search on the subject, but good enough for s start—revealed almost no sources from the United States on war and religion for the era ca 1800 to 1861. There were numerous works from British clerics and soldiers, as well as French works as well. A search in Spanish turned up numerous peiodicals and a book as well, El Soldado Católico en Guerra de Religion: Carta Instructiva, first printed in 1795 and then reissued in 1814. The authors of The Catholic Soldier, a priest named Fr Diego Joseph de Cadiz, and an army officer, Don Antontio Ximenez y Caamaño, offered their work as an instruction book to Catholic soldiers on how to fight as good Catholics, in the service of a Catholic cause. Works like The Catholic Soldier weren’t limited to Spain or even Catholic Countries. British divines wrote sermons, and published books and pamphlets, all entitled The Christian Soldier, Thomas Watson (1810), Samuel Lowell (1813), John Fordyce and Pascow Grenfell (both 1853). There were a variety of variations—the Christian Soldier’s March, the Influence of Christianity on the Military, etc, but the number of titles point to the fact that one group of Anglophone Protestants—Britons—talked about Christian soldiers as Christian soldiers regularly, and another—Americans—did not, at least until 1861.
One explanation might be that Britain fought wars more regularly than the United States did, but that is an overstatement. Americans fought Indian Wars throughout the first half of the 19th Century and foreign enemies twice, in the War of 1812 and the Mexican War. There were undoubtedly religious contours in the latter; John Pinheiro’s Missionaries of Republicanism offers useful coverage of the nexus of Protestantism and republicanism in the Mexican War. But most of the works about religion and warmaking written in the era weren’t by orthodox Protestants. There were anti-war tracts, often written by Unitarians. US Grant, a devout Methodist, had his own qualms about the morality of the Mexican War, but he seems to have not had any vocal opinion one way or the other on whether being a Christian soldier. In fact until the Civil War there does not have seemed to have been much interest in Christian soldiery as Christian soldiers and not as Americans. The great revivals in the Confederate Army, and—as Richard Carwardine notes in his Righteous Strife: How Warring Religious Nationalists Forged Lincoln’s Union—the North’s reliance on religious nationalism to sustain the war effort for the first time brought the idea of the Christian soldier to the American conscience. Nonetheless, for the first seventy years of the American republic’s life, a largely Christian society, governed by a republican government infused with Christian legal and moral precepts, seems to have not conceived of its soldiers as Christian soldiers as such. Republican soldiers, yes, and even at times democratic soldiers, but not Christian soldiers.
In 2025 the question of the relationship of Christianity and warmaking, and the idea of the Christian soldier, seems pertinent. Army Maj. Pete Hegseth, the new Secretary of Defense, is a communicant in good standing in a Reformed church and publicly associates the idea of Christian soldiery with the maintenance of the West and American freedom. More particularly, Hegseth believed that “a painful reformation like the one Christianity eventually emerged from” was what Islam lacked. That same Reformation was what secured to the modern West “peace over violence, equality over slavery, and separation of religion and state.” Christian soldiering might not have been a priority ion the Early Republic, but in 2025, at least the Secretary of Defense believes its worth thinking about.