In 2011, the Republican-controlled state legislature in Wisconsin redrew the legislative boundaries in a way that overwhelmingly favors Republicans and disadvantages Democrats. As a result, in elections the following year, Republicans won 60% of the state assembly despite only receiving 46% of votes cast statewide.
The redrawing of districts for the purposes of empowering one group at the expense of others is known as Gerrymandering. While the US Supreme Court has long held that gerrymandering with the intent of weakening the voting power of racial minorities violates the Constitution, the Court has not yet found gerrymandering based on partisanship unconstitutional. This may soon change as the Supreme Court has now agreed to hear a challenge to the Republicans’ partisan gerrymandering in Wisconsin.