Is the Republican gerrymander after the 2010 census the only reason for the GOP’s dominance of the Wisconsin Legislature?
Although Republican lawmakers redrew legislative districting maps in 2011 that in effect highly favored their electoral outcomes in the Wisconsin State Legislature, experts have argued that Wisconsin’s natural political geography also is somewhat biased in favor of Republicans.
A University of Michigan study simulating several different redistricting scenarios found, "Wisconsin’s natural political geography, combined with a nonpartisan process following traditional districting principles, could plausibly produce a plan with a modest amount of Republican-favoring electoral bias."
Analysis from Marquette University Law School agreed, concluding that Republicans enjoy "a basic structural advantage" and that any map drawn in the 2020s probably would still favor the GOP — even if Democrats got 51% of the vote.
However, both studies confirmed that the 2011 redistricting by Republicans intentionally produced "extreme electoral bias."