Although much is known about the political stance of the military at large during the Civil War, the political party affiliations of individual soldiers have received little attention. Drawing on archival sources from twenty-five generals and 250 volunteer officers and enlisted men, John Matsui offers the first major study to examine the ways in which individual politics were as important as military considerations to battlefield outcomes and how the experience of war could alter soldiers’ political views. The conservative war aims pursued by Abraham Lincoln and his generals in the first year of the American Civil War focused on the preservation of the Union and the restoration of the antebellum status quo. This approach was particularly evident in the prevailing policies and attitudes toward the Confederacy-supporting Southern civilians and African American slaves. But this changed in Virginia during the summer of 1862 with the formation of the Army of Virginia. If the Army of the Potomac (the major Union force in Virginia) was dominated by generals who concurred with the ideology of the Democratic Party, the Army of Virginia was its political opposite, from its senior generals to the common soldiers. The majority of officers and soldiers in the Army of Virginia saw slavery and pro-Confederate civilians as crucial components of the rebel war effort and blamed them for prolonging the war. Ultimately, the frustrating occupation experiences of the Army of Virginia radicalized them and other Union soldiers against Southern rebellion and slavery, paving the way for Abraham Lincoln to issue the Emancipation Proclamation.

During his first inaugural address, Abraham Lincoln expressed hope that the "better angels of our nature" would prevail as war loomed. He was wrong. The better angels did not, but for many Americans, the evil ones did. War Is All Hell peers into the world of devils, demons, Satan, and hell during the era of the American Civil War. It charts how African Americans and abolitionists compared slavery to hell, how Unionists rendered Confederate secession illegal by linking it to Satan, and how many Civil War soldiers came to understand themselves as living in hellish circumstances. War Is All Hell also examines how many Americans used evil to advance their own agendas. Sometimes literally, oftentimes figuratively, the agents of hell and hell itself became central means for many Americans to understand themselves and those around them, to legitimate their viewpoints and actions, and to challenge those of others. Many who opposed emancipation did so by casting Abraham Lincoln as the devil incarnate. Those who wished to pursue harsher war measures encouraged their soldiers to "fight like devils." And finally, after the war, when white men desired to stop genuine justice, they terrorized African Americans by dressing up as demons. A combination of religious, political, cultural, and military history, War Is All Hell illuminates why, after the war, one of its leading generals described it as "all hell."

In Millenarian Dreams and Racial Nightmares, John H. Matsui argues that the political ideology and racial views of American Protestants during the Civil War mirrored their religious optimism or pessimism regarding human nature, perfectibility, and the millennium. While previous historians have commented on the role of antebellum eschatology in political alignment, none have delved deeply into how religious views complicate the standard narrative of the North versus the South. Moving beyond the traditional optimism/pessimism dichotomy, Matsui divides American Protestants of the Civil War era into ""premillenarian"" and ""postmillenarian"" camps. Both postmillenarian and premillenarian Christians held that the return of Christ would inaugurate the arrival of heaven on earth, but they disagreed over its timing. This disagreement was key to their disparate political stances. Postmillenarians argued that God expected good Christians to actively perfect the world via moral reform-of self and society-and free-labor ideology, whereas premillenarians defended hierarchy or racial mastery (or both). Northern Democrats were generally comfortable with antebellum racial norms and were cynical regarding human nature; they therefore opposed Republicans' utopian plans to reform the South. Southern Democrats, who held premillenarian views like their northern counterparts, pressed for or at least acquiesced in the secession of slaveholding states to preserve white supremacy. Most crucially, enslaved African American Protestants sought freedom, a postmillenarian societal change requiring nothing less than a major revolution and the reconstruction of southern society. Millenarian Dreams and Racial Nightmares adds a new dimension to our understanding of the Civil War as it reveals the wartime marriage of political and racial ideology to religious speculation. As Matsui argues, the postmillenarian ideology came to dominate the northern states during the war years and the nation as a whole following the Union victory in 1865.