U.S. Supreme Court justices will hear arguments Monday on whether the boundaries of 11 Virginia House of Delegates districts were drawn on the basis of race by Republicans.

Many Virginians will be keeping a close eye on the U.S. Supreme Court Monday, as justices hear arguments in the state’s fight over allegations of racial gerrymandering.

The main question: Whether the boundaries of 11 Virginia House of Delegates districts were drawn on the basis of race by Republicans.

Last year, a federal court ruled that the boundaries were unconstitutional because black voters were concentrated in certain areas. The court later approved new district lines that would likely make it difficult for Republicans to retain their current power in the General Assembly.

House Republicans will try to convince justices that the initial racial gerrymandering ruling should be thrown out.

An analysis of the new boundaries by the nonpartisan Virginia Public Access Project shows the map could shift six Republican-held districts toward Democrats, including the district of House Speaker Kirk Cox, which would become 32 percent more Democratic. Cox called the map approved by the court “legally indefensible” and said it attempts to “give Democrats an advantage at every turn.”

In addition to Cox, Del. Chris Jones, R-Suffolk, chairman of the House Appropriations Committee, would see a sharp Democratic shift of 27.4 percentage points in his district, under the Virginia Public Access Project’s analysis.

Del. David Yancey, R-Newport News, whose 2017 re-election race ended in a tie, would also see a significant Democratic shift — 13.6 percentage points — in his district. Control of the House was decided when Yancey’s name was drawn from a bowl, allowing him to hold on to his seat over his Democratic challenger.

Democrats made huge gains in the 2017 House election, wrestling 15 seats away from Republicans.

Despite that, Republicans held on to a slim majority, a result some Democrats said showed that gerrymandering insulated Republicans from the will of the voters.

Republicans currently hold a 51-49 majority in the House.

All 100 House seats and all 40 Senate seats will be on the ballot this year in November.

The Associated Press contributed to this report.