**This definitive analysis of the Lincoln-Douglas debates is one of the most influential works of American history and political philosophy ever published** **( *National Review* ).** In *Crisis of the House Divided* , noted conservative scholar and historian Harry V. Jaffa illuminates the political principles that guided Abraham Lincoln from his reentry into politics in 1854 through his Senate campaign against Stephen Douglas in 1858. Through critical analysis of the Lincoln-Douglas debates, Jaffa demonstrates that Lincoln’s political career was grounded in his commitment to constitutionalism, the rule of law, and abolition. A landmark work of American history, it has shaped the thought of a generation of Abraham Lincoln and Civil War scholars. To mark the fiftieth anniversary of the original publication, Jaffa has provided a new introduction ( *Civil War History* ). **A searching and provocative analysis of the issues confronted and the ideas expounded in the great debates…A book which displays such learning and insight that it cannot fail to excite the admiration even of scholars who disagree with its major arguments and conclusions.–D. E. Fehrenbacher, *American Historical Review***