The justices ruled that the Republican-controlled House of Delegates lacked the authority to challenge a federal district court decision striking down the maps after the state's Democratic attorney general refused to do so.
The decision was written by Associate Justice Ruth Bader Ginsburg, who was joined by two conservative and two liberal colleagues. Associate Justice Samuel Alito dissented and was joined by Chief Justice John Roberts and Associate Justices Stephen Breyer and Brett Kavanaugh.
"Virginia would rather stop than fight on," Ginsburg wrote. "One House of its bicameral legislature cannot alone continue the litigation against the will of its partners in the legislative process."
By dismissing the GOP's challenge, the high court gave Democrats a better chance of winning control of the state legislature in November. Currently, Republicans hold slim, two-seat advantages in the House, as well as the Senate. Democrats have not controlled the legislature in a quarter-century.
The decision leaves intact the recent primary elections in Virginia, where voters go to the polls in odd-numbered years to elect state officials. Some races were held in districts redrawn by the district court to favor Democrats after it ruled that Republicans' maps were designed to dilute African Americans' voting strength.
While the high court gave Democrats a victory, it did not take sides on the threshold issue: whether the maps followed or violated the Voting Rights Act, which says minorities must be given a chance to elect lawmakers of their choice. That requires a balancing act: Districts should have enough minority voters but not too many, lest their votes are diluted in surrounding areas.

While the Supreme Court has ruled many times on the use of race in redistricting, it has never found a standard for how much politics is too much.
The Virginia case involved 11 state House districts drawn by Republican lawmakers to ensure that at least 55% of the voters were African Americans. The federal district court ruled last year that was unnecessarily excessive.
It was the second time the high court has ruled on the case. In 2017, it sided with challengers in demanding further review of the districts by the lower court. That 7-1 ruling was a temporary victory for Democrats.
The Voting Rights Act of 1965 requires states to draw districts that enable African-Americans to elect their chosen representatives, lest blacks not form a majority anywhere.
Two decades ago, Democrats used the law to demand "majority-minority" districts. After Republicans took over many state legislatures in 2010, they began drawing districts with what critics claimed were more African-Americans than necessary, in order to protect surrounding districts.

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