The case arguing that Republicans rig congressional districts to favor the GOP is continuing in Pennsylvania’s highest court. On Wednesday, Democratic voters testified in the Pennsylvania Supreme Court claiming gerrymandering is depriving the constituency of their freedom of speech.

The way district lines are drawn can influence the outcome of elections, regardless of how voters turn out. The redistricting done to Pennsylvania resulted in the Democratic party losing two seats in 2012, with a final outcome of Republicans holding 13 seats and Democrats holding 5. However, it can be argued, and Democrats do, that the final distribution of seats should have been different because Democrats won more than 50% of the popular vote.

Republicans argue that many factors have to be taken into account to draw district lines such as population, the Voting Rights Act, as well as data on how each district votes. Pennsylvania’s second congressional district votes heavily democratic in congressional elections, and in 2012 Democrat Chaka Fattah won with 89% of the vote. However, in the 2016 election, the same district voted for President Trump.

Another component making this issue is so tricky is because of how congressional seats operate as representatives of geographical area, instead of just the general populous. This prevents large urban centers from dominating the policy of rural areas. It also creates the problem of those large population areas not being as relevant in the overall vote. A balance between rural areas and populated areas is a common complication in America’s electoral system, as is common, for example, in the presidential election.

Federal judges ruled on Pennsylvania’s congressional map earlier this month 2-1 to uphold the map, but not because it had any opinion on how the lines should be drawn. Rather, the majority opinion was that the issue was inappropriate for a court to decide and instead should be resolved within other parts of the political structure.

However, a court in North Carolina ruled that its state’s GOP drawn congressional map was unconstitutional and had to be redrawn. The resolution to the gerrymandering debate across the country will likely be resolved when the Supreme Court rules on Wisconsin’s congressional map in Gill v Whitford.