How did the KKK affect history?

The Ku Klux Klan (not klu, but ku) is often abbreviated as K.K.K. This particular white supremacist group thinks that whites are better than all other races, and they unleashed their hatred among African-Americans after the Civil War. Wearing white robes and hats, they attacked anyone who supported African-Americans and the 14th and 15th Amendment. Republicans were often attacked because of their support in African-American rights, and as a result Democrats began to rise to power in 1868. Even though Republican Ulysses S. Grant became President, many Republicans left office and "Negros" refused to vote due to the KKK attacks and death threats. Some KKK even openly held firearms at voting booths during elections and threatened blacks, making African Americans unable to actually advocate or vote for people that supported their rights. This led to a century of racism, bias, and violence towards African-Americans before their rights were recognized and they were treated as equals.