Final answer:
Northern support for Reconstruction declined in the 1870s due to the shift in focus towards economic recovery after the Panic of 1873, the growth of conservative power in the South, political changes that reduced congressional commitment to Reconstruction, and a desire to move beyond the policies of Reconstruction that was evident in the Compromise of 1877.
Step-by-step explanation:
During the 1870s, Northern support for Reconstruction began to wane. This decline in support was due to several factors. The Panic of 1873, an economic depression, shifted the focus of many Americans from the issues of the Reconstruction to the more immediate concerns of economic recovery. Additionally, rampant violence in the South, including the actions of the Ku Klux Klan and other White supremacist groups, made the prospect of reform seem insurmountable. Political changes, such as the Democratic wins in the 1874 midterm elections, signaled a reduced congressional commitment to Reconstruction. Furthermore, by the time of the contested presidential election of 1876, both candidates suggested that their victory would mark the end of Reconstruction, indicating a general sentiment towards moving beyond these policies. This all culminated in the Compromise of 1877, where Republican Rutherford B. Hayes assumed the presidency and, as part of a deal with Southern Democrats, withdrew federal troops from the South, effectively ending Reconstruction.