Final answer:
The Klan was notably powerful in the Midwest, especially in Indiana, which had around 350,000 Klan members. This rise of power outside the traditional Southern stronghold was surprising and indicative of the Klan's extensive reach into society and politics during the 1920s.
Step-by-step explanation:
The Klan became increasingly powerful in the Midwest. This may indeed be a location surprising to many, considering that the Klan is often associated with the South due to its origins and significant presence there during the Reconstruction era. However, during the 1920s, the second incarnation of the Ku Klux Klan saw a substantial rise in membership in the Midwest, with Indiana being notably powerful, boasting an estimated 350,000 Klansmen. The Klan's influence extended into public policy, as seen in Oregon where legislators with Klan ties supported a referendum that aimed to ban private schools, targeting the Catholic Church. The extent of this organization's reach through various sectors of society demonstrates how pervasive and mainstream the Klan had become during this period, reflecting broader national patterns of anti-immigrant and racist sentiment.