Basically--and significantly--this is a book about the durability of American constitutional principles in the Civil War and Reconstruction periods. Congressional Republicans, Belz maintains, checked arbitrary executive power during the war and afterwards avoided the sacrifice of federalism to centralized government while expanding the meaning of republicanism to incorporate legal equality for the freedmen. The great majority of Republicans denied that the war abrogated the Constitution, the author notes, and Congress actively regulated the executive exercise of war powers. Belz' evaluation of Reconstruction is particularly acute because, refusing to take for granted what is normally accepted as inevitable, he is able to provide a new perspective. Congress, he observes, might simply have dismantled the rebel states. But guided by the principle of federalism, even Radical Republicans sought to promote the restoration of the secessionist states through voluntary reorganization by their inhabitants, though with stipulations aimed at protecting freedmen's rights. He shrewdly notes that the very insistence upon those stipulations--e.g., ratification of the 14th amendment--indicated Congress' assumption that the states would soon recover their local authority with antebellum powers essentially intact. Negro suffrage, the ultimate requirement, is seen as an attempt to secure black legal equality without permanent federal intervention. In sum, Belz skillfully argues that Reconstruction was constitutionally moderate. But, responding to recent Leftist historiography that disparages the accomplishments of Reconstruction, he observes that from a political viewpoint it had a radical impact. Evaluating history in context rather than through 20th-century political programs, Belz recognizes that Reconstruction spared freedmen the legal status akin to apprenticeship that Southern whites were preparing for them in 1865. For this reason alone (and Belz cites others), the impact of Reconstruction was substantial. A formidable work by a specialist in the period.