Final answer:
The federal government pulled out troops after Reconstruction, failing to protect African Americans from racial violence after initial efforts under the Enforcement Acts weakened due to economic concerns and loss of political will.
Step-by-step explanation:
The best statement that describes the federal government’s response to racial violence in the South in the late 1800s is that the federal government pulled out troops from the South at the end of Reconstruction, leaving African Americans unprotected. Initially, the Enforcement Acts between 1870 and 1871 were passed, which made it a crime to interfere with African Americans' civil rights, and the use of U.S. troops was permitted to protect freedpeople from violence, particularly from the Ku Klux Klan. President Grant used these powers in South Carolina, and the newly created Department of Justice worked to uphold these federal laws. However, as the cost of enforcing these protections grew and opposition to Radical Reconstruction stiffened, interest in these policies waned. The Panic of 1873 and subsequent Democratic victories led Congress to refrain from further enforcement measures, focusing on economic recovery instead. Consequently, federal troops were withdrawn in 1877, and control of the South fell back into the hands of White Democrats who used violence to suppress Black citizens’ rights.