Like many nativist organizations opposed to immigration, the Knights of the Ku Klux Klan responded to cultural changes brought about not only by immigration, but also by changes in the American economy and society after the First World War. Rapid technological, economic, demographic, social, and cultural changes understandably created confusion and cultural tension in the early 1920s. Mass production, mass consumption, mass communications, and mass culture undermined the familiar cultural codes and traditional morals and values. The Ku Klux Klan attempted to resist challenges to traditional morality by enlisting native, white, Protestant Americans who exhibited character, morality, Christian values, and "pure Americanism."

Most Americans today imagine the average Klansman as a bigoted, intolerant, ignorant, southern redneck who burned crosses, terrorized black Americans, and intimidated opponents while hiding behind white sheets and a conical hood. While many of these images are based in fact, the Klan of the 1920s had little in common with the Klan of the 1860s or of the 1960s. The second of five distinct Klan eras, the Klansmen of the 1920s resembled fraternal, temperance, and progressive reform organizations, albeit with a coercive (and sometimes downright terrorist) edge. In their effort to preserve an idealized "golden age" of American life, most Klan activities focused on defending white, Christian civilization, promoting community activities, enforcing morality, and combating corruption and concentrated economic power. Most of the Klan's political activity was local, non-partisan, and aimed at enforcing morality and sobriety. One of the Klan's most important moral campaigns was for the restoration of law and order as exemplified by adherence to the 18th Amendment.

Read Frederick Lewis Allen's account of the Klan.