Wisconsin was once one of the most progressive states in the US. Consider what it is now.
After losing in the 1932 Republican Primary, Phillip and Robert La Follete split off to form the Wisconsin Progressive Party, an established wing of the Republican party active in other states at that time. In 1934 the Progressives took power in gubernatorial and federal senate races, and in 1936 swept into power in the state senate. The Republican and Democratic parties eventually ran a unified ticket in 1938 to break the back of the Progressives although several members lasted deep into the 1940s.