The U.S. Supreme Court appeared to be struggling Wednesday with how to address voting maps drawn to give the political party in power an extreme advantage over the other, as the justices gathered for the second time this term to hear a case involving partisan gerrymandering.

The case before the justices challenged the boundaries of Maryland’s 6th Congressional District drawn by Democrats. The plaintiffs in the case, Republican voters, argue the lines were drawn to give Democrats an advantage, diluting their votes and violating their free speech rights.