The Supreme Court recently agreed to hear arguments on partisan gerrymandering in a contested map drawn in the state of Wisconsin. The Supreme Court has ruled that districts must be of equal size and that districts drawn explicitly along racial lines violate the Voting Rights Act of 1965. Beyond these two considerations, a “fair” district has yet to be defined by the courts. Savvy party operatives have taken advantage, manipulating districts to benefit one party(y) or the other, a process understood broadly as “partisan gerrymandering.”

This new Supreme Court case – Gill v. Whitford – may determine the constitutionality of partisan gerrymandering, setting a precedent that will influence redistricting decisions for years to come.

At an alarming rate, “safe” congressional districts are growing and contributing to much of the divisiveness we see in today’s political rhetoric. According to an analysis conducted by the Cook Political Report, the number of swing districts, or districts that are competitive in the general election, have been cut in half from 164 in 1996 to 72 in 2016. As a result, candidates have less of an incentive to consider opposing ideologies or policy preferences – further quarantining themselves into their ideological corners.

Despite the role gerrymandering plays in polarization, Brookings Scholars who study gerrymandering generally agree that gerrymandering isn’t the primary source of polarization, and only a fraction of these newly “safe” districts can definitively be pinned to gerrymandering. In fact, The Cook Political Report attributes only 17 percent of all swing district losses to partisan gerrymandering since 1996. An even larger contributor to increasingly “safe” districts is that like-minded people are continuing to concentrate themselves in environments that replicate their own political beliefs – also known as natural geographic sorting.