*Party division totals are based on election day results.
Following the 1862 wartime elections, the Republican majority in the House narrowed while it grew in the Senate. To pay for the Union war effort, legislation creating America’s first progressive income tax took effect and the 38th Congress (1863–1865) sent a constitutional amendment abolishing slavery to the states for review. Anticipating its ratification, Congress created the Freedmen’s Bureau to assist former slaves making the transition into full citizenship. Republican majorities authorized the transcontinental railroad, and welcomed West Virginia and Nevada into the Union. President Abraham Lincoln’s 1864 pocket veto of the Wade-Davis Bill stifled other congressional reconstruction plans.