How did the U.S. government end Reconstruction?

Reconstruction went through different phases, including Presidential Reconstruction under Andrew Johnson in 1865-1866 and Radical Reconstruction under the Radical Republicans in Congress starting in 1867. Johnson's Presidential Reconstruction reflected his belief in states' rights and was relatively lenient, so southern states starting passing "Black Codes," which tied freed slaves to plantations and prevented their unrestricted movements. Under Congressional Reconstruction, the former Confederate states were divided into 5 military districts, and they had to pass the...

Reconstruction went through different phases, including Presidential Reconstruction under Andrew Johnson in 1865-1866 and Radical Reconstruction under the Radical Republicans in Congress starting in 1867. Johnson's Presidential Reconstruction reflected his belief in states' rights and was relatively lenient, so southern states starting passing "Black Codes," which tied freed slaves to plantations and prevented their unrestricted movements. Under Congressional Reconstruction, the former Confederate states were divided into 5 military districts, and they had to pass the 14th Amendment, granting citizenship to all people born in the United States. In 1868, the Congress also passed the 15th Amendment, giving African-American men the right to vote. 

By 1870, all of the former Confederate states had rejoined the Union. At this point, the Ku Klux Klan and other organizations repeatedly interfered with African-Americans' ability to vote and exercise other civil rights, and Ulysses  Grant, then President, passed legislation to attempt to curb the activities of the Klan and other organizations that were attempting to intimate freed slaves. However, Grant refused to send federal troops to enforce the law and end violence in states such as Mississippi. 

The election of 1876 put an end to Reconstruction. Rutherford Hayes, the Republican candidate, was in a disputed election with the Democrat, Samuel Tilden. In exchange for his ability to become President, Rutherford told the Democrats he would end Reconstruction. They agreed, and what followed were decades of "Jim Crow" legislation that effectively limited voting and other civil rights for African-American people in the south, largely until the Civil Rights Movement of the 1950s and 1960s.