Republican Party, led by Robert LaFollette. It went on to reshape this state with progressive legislation. Note that they did this without cooperation from the national Republicans. I think the model for today is clear, with the simple substitution of "Democrats" for "Republicans."
Here are a few paragraphs that outline what happened:
What did the Progressive Movement accomplish in Wisconsin? During James Davidson's terms as governor, from 1906 to 1911, considerable progressive legislation was enacted, including laws proving for state control of corporation stock issues, an extension of the power of the railroad commission to regulate transportation, a fixing of railroad fares, and stricter regulation of insurance companies. The most important and influential progressive legislation, however, was passed during the next (1911) session, under the governorship of Francis McGovern. The 1911 legislature created the nation's first effective workers' compensation program to protect people injured on the job. It passed laws to regulate factory safety, encouraged the formation of cooperatives, established a state income tax, formed a state life insurance fund, limited working hours for women and children, and passed forest and waterpower conservation acts.
While La Follette was the most powerful Progressive political leader in Wisconsin, he was never able to gain complete control over the state's Republican Party or even Wisconsin Progressives. The opening decades of the 20th century were a time of contentious political strife and debate, and not everyone agreed about the goals and strategies of the Progressive program. Progressivism appealed to voters who favored orderly change, rather than a fundamental shift in the economic and social order. Many of the reforms were moderate and thus acceptable to a large number of people who might not otherwise have supported the movement, such as businessmen. Other Wisconsin citizens viewed Progressive reforms as excessive state interference, while many others wanted more sweeping changes such as those advocated by the Socialist Party.
By the 1930s, when depression and unemployment dominated American public life, the assumptions of the Wisconsin Progressives had penetrated deeply into national politics. Much of Franklin Roosevelt's New Deal legislation was drafted by Wisconsin citizens, such as Edwin Witte (author of the 1935 Social Security act), who had been trained by Progressive Wisconsin economics professor John R. Commons. In fact, the momentum of La Follette and his allies rippled down through the decades into John Kennedy's "New Frontier" and Lyndon Johnson's "Great Society" programs.
http://www.wisconsinhistory.org/turningpoints/tp-036/?action=more_essay