BISMARCK, N.D. — In 1918, an offshoot of the progressive farmer-labor movement known as the Nonpartisan League swept into power in North Dakota , riding a populist groundswell of anger directed at big banks and industry barons in Minneapolis and Chicago.

The group was organized by former Socialist Party member Arthur C. Townley, a failed flax farmer who barnstormed the state in a borrowed Ford Model T calling for public ownership of key industries, including banks, mills and factories. By 1919, the state legislature authorized a state-owned and -operated bank.

Over a century later, the Bank of North Dakota still stands, and the state is reaping the benefits.

The Bank of North Dakota is the nation's only surviving state-owned and -operated bank.…