According to britannica.com:
"Statistics of reported lynching in the United States indicate that, between 1882 and 1951, 4,730 persons were lynched, of whom 1,293 were white and 3,437 were black. Lynching continued to be associated with U.S. racial unrest during the 1950s and ’60s, when civil rights workers and advocates were threatened and in some cases killed by mobs."
"Ku Klux Klan (KKK) is the name of several past and present secret organizations in the United States, mostly in the South, that are best known for advocating white supremacy and acting as vigilantes while hidden behind conic masks and white robes. The first KKK arose in the turmoil after the Civil War. It utilized terrorism, violence, and lynching to intimidate and oppress African Americans, Jews as well other racial and religious minorities.
The first Klan was founded in 1866 by veterans of the Confederate Army. Its purpose was to restore white supremacy in the aftermath of the American Civil War. The Klan resisted Reconstruction by intimidating "carpetbaggers", "scalawags" and freedmen. The KKK quickly adopted violent methods. The increase in murders finally resulted in a backlash among Southern elites who viewed the Klan's excesses as an excuse for federal troops to continue occupation. The organization declined from 1868 to 1870 and was destroyed by President Ulysses S. Grant's prosecution and enforcement under the Civil Rights Act of 1871.
In 1915, the second Klan was founded. It grew rapidly in another period of postwar social tensions. After WWI, many Americans coped with booming growth rates in major cities, where numerous waves of immigrants from southern and eastern Europe and the Great Migration of Southern blacks and whites were being absorbed. After WWI, labor tensions rose as veterans tried to reenter the work force. In reaction to these new groups of immigrants and migrants, the second KKK preached racism, anti-Catholicism, anti-Communism, nativism, and anti-Semitism. Some local groups took part in lynchings, attacks on private houses and public property, and other violent activities. Members used ceremonial cross burning to intimidate victims and demonstrate its power. Murders and violence by the Klan were most numerous in the South, which had a tradition of lawlessness.
The film The Birth of a Nation and the sensationalized newspaper coverage of the trial, conviction and lynching of Leo Frank of Georgia sparked the Klan's revival. The second Klan was a formal fraternal organization, with a national and state structure. At its peak in the mid-1920s, the organization included about 15% of the nation's eligible population, approximately 4–5 million men. The Klan's popularity fell rapidly during the Great Depression, and membership fell further during World War II.
The name 'Ku Klux Klan' has since been used by many independent groups opposing the Civil Rights Movement and desegregation, especially in the 1950s and 1960s. During this period, they often acted with impunity by alliances with Southern police departments, as during the reign of Bull Connor in Birmingham, Alabama; or governor's offices, as with George Wallace of Alabama. Several members of KKK-affiliated groups were convicted of manslaughter and murder in the deaths of civil rights workers and children in the bombing of the 16th Street Baptist Church in Alabama, the assassination of NAACP organizer Medgar Evers, and the murders of three civil rights workers in Mississippi. Today, researchers estimate there may be more than 150 Klan chapters with 5,000-8,000 members nationwide. The U.S. government classifies them as hate groups, with operations in separated small local units. The modern KKK has been repudiated by all mainstream media, political and religious leaders.
Klan violence worked to suppress black voting. As examples, over 2,000 persons were killed, wounded and otherwise injured in Louisiana within a few weeks prior to the Presidential election of November 1868. Although St. Landry Parish had a registered Republican majority of 1,071, after the murders, no Republicans voted in the fall elections. White Democrats cast the full vote of the parish for Grant's opponent. The KKK killed and wounded more than 200 black Republicans, hunting and chasing them through the woods. Thirteen captives were taken from jail and shot; a half-buried pile of 25 bodies was found in the woods. The KKK made people vote Democratic and gave them certificates of the fact.
By 1868, two years after the Klan's creation, its activity was beginning to decrease. Members were hiding behind Klan masks and robes as a way to avoid prosecution for free-lance violence. Many influential southern Democrats feared that Klan lawlessness provided an excuse for the federal government to retain its power over the South, and they began to turn against it. There were outlandish claims made, such as Georgian B.H. Hill stating "that some of these outrages were actually perpetrated by the political friends of the parties slain."
Others may have agreed with lynching as a way of keeping dominance over black men. In many states, officials were reluctant to use black militia against the Klan from fear that race tensions would be raised. When Republican Governor of North Carolina William Woods Holden called out the militia against the Klan in 1870, it added to his unpopularity. Combined with violence and fraud at the polls, in the election, the Republicans lost their majority in the state legislature. Disaffection with Holden's actions led to white Democratic legislators' impeaching Holden and removing him from office, but their reasons were numerous.
National sentiment gathered to crack down on the Klan, even though some Democrats at the national level questioned whether the Klan existed or was a creation of nervous Southern Republican governors. Many southern states began to pass anti-Klan legislation.
In January 1871, Pennsylvania Republican Senator John Scott convened a Congressional committee which took testimony from 52 witnesses about Klan atrocities. They accumulated 12 volumes of horrifying testimony. In February, former Union General and Congressman Benjamin Franklin Butler of Massachusetts introduced the Ku Klux Klan Act. This added to the enmity southern white Democrats bore toward him. While the bill was being considered, further violence in the South swung support for its passage. The Governor of South Carolina appealed for federal troops to assist his keeping control. A riot and massacre in a Meridian, Mississippi, courthouse were reported, from which a black state representative escaped only by taking to the woods.
The nadir of American race relations is often placed from the end of reconstruction to the 1910s, especially in the South. Once white Democrats regained political power in state legislatures in the 1870s, they passed bills directed at restricting voter registration by blacks and poor whites. Continued low cotton prices, agricultural depression and labor shortages in the South contributed to social tensions. According to Tuskegee Institute, the 1890s was also the peak decade for lynchings, with most of them directed against African Americans in the South. The lynchings were a byproduct of political tensions as white Democrats tried to strip blacks from voter rolls and suppress voting. Some of the violence was directed at trying to break up interracial coalitions that came to power in state legislatures in 1894, with alliances of Populist and Republican parties. In 1896, the Democrats used fraud, violence and intimidation to suppress voting by poor classes, and regained power.
Director D. W. Griffith's The Birth of a Nation glorified the original Klan. His film was based on the book and play "The Clansman" and the book "The Leopard's Spots," both by Thomas Dixon. Dixon said his purpose was "to revolutionize northern sentiment by a presentation of history that would transform every man in my audience into a good Democrat!" The film created a nationwide Klan craze. At the official premier in Atlanta, members of the Klan rode up and down the street in front of the theater.
In 1921, the Klan arrived in Oregon from central California and established the state's first klavern in Medford. In a state with one of the country's highest percentages of white residents, the Klan attracted up to 14,000 members and established 58 klaverns by the end of 1922. Given small population of non-white minorities outside Portland, the Oregon Klan directed attention almost exclusively against Catholics, who numbered about 8% of the population. In 1922, the Masonic Grand Lodge of Oregon sponsored a bill to require all school-age children to attend public schools. With support of the Klan and Democrat Governor Walter M. Pierce, endorsed by the Klan, the Compulsory Education Law was passed with a majority of votes. Its primary purpose was to shut down Catholic schools in Oregon, but it also affected other private and military schools. It was challenged in court and struck down by the United States Supreme Court Pierce v. Society of Sisters (1925) before it went into effect.
In effect, the Klan defended the interest of the planter class and Democratic Party by working to curb the education, economic advancement, voting rights, and right to keep and bear arms of blacks. The Ku Klux Klan soon spread into nearly every southern state, launching a "reign of terror" against Republican leaders both black and white. Those political leaders assassinated during the campaign included Arkansas Congressman James M. Hinds, three members of the South Carolina legislature, and several men who served in constitutional conventions."
As historian Elaine Frantz Parsons discovered,
“Lifting the Klan mask revealed a chaotic multitude of antiblack vigilante groups, disgruntled poor white farmers, wartime guerrilla bands, displaced Democratic politicians, illegal whiskey distillers, coercive moral reformers, bored young men, sadists, rapists, white workmen fearful of black competition, employers trying to enforce labor discipline, common thieves, neighbors with decades-old grudges, and even a few freedmen and white Republicans who allied with Democratic whites or had criminal agendas of their own. Indeed, all they had in common, besides being overwhelmingly white, southern, and Democratic, was that they called themselves, or were called, Klansmen."
As historian Eric Foner observed,
“In effect, the Klan was a military force serving the interests of the Democratic party, the planter class, and all those who desired restoration of white supremacy. Its purposes were political, but political in the broadest sense, for it sought to affect power relations, both public and private, throughout Southern society. It aimed to reverse the interlocking changes sweeping over the South during Reconstruction: to destroy the Republican party's infrastructure, undermine the Reconstruction state, reestablish control of the black labor force, and restore racial subordination in every aspect of Southern life."