Final answer:
The rebirth of the KKK in the 1920s was fueled by nativist attitudes and social anxiety among native-born whites, along with a desire for fraternity and the defense of traditional values in the face of demographic and cultural changes.
Step-by-step explanation:
The resurgence of the Ku Klux Klan (KKK) in the 1920s was driven by multiple factors. One prominent factor was the spread of nativist sentiments and the fear of losing a perceived 'white, Protestant heritage,' which was magnified by the popularization of racist and nativist ideologies through media such as D. W. Griffith's film Birth of a Nation and the influence of eugenics.
The KKK capitalized on these fears by promoting anti-Black, anti-immigrant, anti-Catholic, and anti-Semitic philosophies. Another significant factor was the economic and social anxieties of the 1920s, which led many to find scapegoats for their problems in ethnic minorities and immigrants, driving them towards organizations like the KKK that promised to defend their traditional way of life and values.
Additionally, the Klan's ability to present itself as a fraternal organization offering a sense of community and identity through social gatherings, rituals, and the appeal to 'old-time religion' and 'family values' attracted numerous middle-class Americans. This fraternity aspect made the KKK not solely attractive to disenfranchised individuals but also to those in the mainstream society who felt their cultural hegemony threatened by rapid social changes and demographic shifts.