This dissertation examines the dominant social and political mindset of northern white evangelicals during the Civil War and Reconstruction. Relying upon sermons, serial publications, and archival and presidential papers, it follows a standard political narrative. Particular attention is given to evangelical interaction with the presidencies of Abraham Lincoln, Andrew Johnson, and Ulysses S. Grant. The mindset explored here combined a traditional evangelical proprietary and covenantal regard for America with Unionism and republicanism. This dissertation argues that non-radical evangelicals consistently subordinated concern for the slaves and freedmen to an abstract vision for their Christian republic throughout the period. These evangelicals went to war to save the Union, with emancipation instrumental, yet incidental, to the cause of Union and the preservation of a Christian people under God's providential hand. Such evangelicals entered Reconstruction expecting to see the emergence of a speedily restored and culturally homogeneous Union. That securely restored Union would be one in which evangelicalism would be even more culturally dominant than had been the case during the antebellum period.The study primarily intersects with four historiographies. First, examining the intersection of the northern evangelical proprietary impulse with widespread devotion to the Union contributes to the body of scholarship on Unionism that has only tangentially recognized the overlap with evangelicalism. The mainstream evangelical vision for the Union, with strong antebellum ties, retained significant ethno-cultural elements and was not synonymous with the civic-nationalist vision put forth by abolitionist evangelicals. Second, this dissertation shifts attention away from radicals and millennialism as the primary loci for understanding northern Protestantism and the Civil War to the more encompassing idea of Union. Third, focusing on evangelical Unionism also contributes to our understanding of the place and importance of religion in relation to Reconstruction and the failure of the federal government to adequately prepare the ex-slaves for freedom; evangelical Unionists consistently functioned as a brake on radical visions for a racially equitable and inclusive American Union. Finally, evangelical Unionism forged during the Civil War era is a significant part of the background for the Fundamentalist-Modernist controversy and thus contributes to our understanding of the Religious Right's historical origins.