The U.S. Supreme Court will hear arguments Tuesday over whether Arizona’s redistricting commission illegally diluted the voting power of nearly two million Arizonans – specifically Republicans and non-minority voters – when the commission redrew the state’s legislative districts in 2011.

The lawsuit is based on the fact that the state’s Republican-leaning legislative districts are overpopulated, while Democratic-leaning and minority-heavy districts are underpopulated.

The court could rule that the current maps violate the one person, one vote equal protection clause of The U.S. Constitution. The appellants want the commission to redraw the maps, which would tilt the state legislature further in favor of Republicans. The Arizona House of Representatives has 36 Republicans and 24 Democrats, and the Senate is composed of 18 Republicans and 12 Democrats.

Such a ruling could immediately open the door for similar litigation in more than a dozen other states where state legislative district populations are not exactly equal.