Why did US President Ulysses S. Grant propose and then sign the Enforcement Act of 1871?

The 'Enforcement Act of 1871' is also known by a number of additional names: the 'Civil Rights Act of 1871', 'Force Act of 1871', the 'Ku Klux Klan Act', 'Third Enforcement Act', or 'Third Ku Klux Klan Act'.

It was an Act of the US Congress, signed by President Grant that empowered the President to suspend the writ of 'habeas corpus' (Latin- meaning to produce a body) to combat the Ku Klux Klan and other white supremacy organizations. It was signed on April 20, 1871.

The Act was the last of three 'Enforcement Acts' passed during the Reconstruction Era (1863 to 1877) to combat attacks upon the suffrage rights of African Americans. It has been subject to only minor changes since then, but has been the subject of voluminous interpretation by courts. The official long title is, 'An Act to enforce the Provisions of the Fourteenth Amendment to the Constitution of the United States and for other Purposes'.

The legislation was asked by President Grant and passed within one month. Grant's request was a result of the reports he was receiving of widespread racial threats in the Deep South, particularly in South Carolina. The Act gave the President the power for the first time to both suppress state disorders on his own initiative and to suspend the right of 'habeas corpus'.

As a result, the first era of the KKK was completely dismantled and did not resurface in any meaningful way until the first part of the 20th century.