In the midterm elections of 1862, which concluded on November 4, the Lincoln administration and the Republican Party suffered a serious setback at the polls. Proclaiming “the Constitution as it is and the Union as it was,” Democrats pointed to the promised Emancipation Proclamation and Lincoln’s recent nationwide suspension of the writ of habeas corpus as evidence of the Republicans’ desire to impose a tyrannical dictatorship upon the republic. Nor did the prospects for decisive military victory seem bright:...