By the mid-1870s, the United States was experiencing a significant political transformation following the Civil War and the Reconstruction period. The goals of Reconstruction included rebuilding the South, integrating formerly enslaved people into society, and restoring Southern states to the Union. However, by the end of the 1870s, the Reconstruction efforts were rolled back significantly, leading to the implementation of Jim Crow laws. Which of the following developments most directly contributed to the end of Reconstruction?