The U.S. Supreme Court is scheduled to hear arguments Wednesday on a lawsuit alleging partisan gerrymandering in the drawing of a Maryland congressional district. Eight years after the 2010 Census provided the basis for legislative redistricting, several other cases alleging unconstitutional gerrymandering in various states also are still working their way through the court system.

In Pennsylvania, a recent court ruling reshaped congressional districts for this year's elections. But many of the other cases could have a greater impact in the years to come. That's because they could set precedents that states must follow during the next round of redistricting after the 2020 Census.

Here's a look at some key redistricting cases ruled upon recently or still pending in courts: A federal court in November 2016 struck down Wisconsin's state Assembly districts enacted in 2011 by the Republican-led Legislature and Republican governor as an unconstitutional partisan gerrymander in violation of Democratic voters' rights to representation. The U.S. Supreme Court heard arguments in October 2017 and has yet to rule in the case. It could set a precedent for whether and how courts can determine if partisan gerrymandering is unconstitutional.