During what time period did the Nonpartisan League primarily operate in North Dakota?

The Nonpartisan League primarily operated in North Dakota during the 1920s, a pivotal time for the organization. Established in 1915, the League aimed to address the economic and political concerns of farmers and working-class individuals who felt that their interests were not represented by the major political parties. The 1920s marked a peak in the League's influence, as it successfully gained significant political power in North Dakota.

During this period, the League promoted policies that focused on agricultural reform, cooperative enterprises, and government-run initiatives to help farmers, such as state-owned enterprises in grain marketing and insurance. The League's impact was notable in the 1920s, resulting in a significant transformation in North Dakota's political landscape, including the election of Nonpartisan League candidates to the state legislature and the governorship.

In contrast, the other time periods mentioned were either before the League's formation or later periods when its influence had waned. The 1860s were characterized by a different set of historical events, particularly the post-Civil War era and westward expansion. The 1940s and 1960s saw diminishing influence of the League, as its original goals were either achieved or transformed over time and the political environment changed significantly