Democrats on Monday filed an emergency appeal with the U.S. Supreme Court seeking to halt a Virginia ruling invalidating a ballot measure that would have given their party an additional four winnable U.S. House seats.Related video above: Republican redistricting edge widens after Democratic setback in VirginiaThe move came after the Virginia Supreme Court on Friday struck down a constitutional amendment that voters narrowly passed just last month. The 4-3 state court decision found that the Democratic-controlled legislature improperly began the process of placing the amendment on the ballot after early voting had begun in the Virginia's general election last fall.Democrats argued unsuccessfully that the U.S. Supreme Court has held that, even if early voting is underway, an election does not happen until Election Day itself.The appeal is the latest twist in the nation’s mid-decade redistricting competition. It was kicked off last year by President Donald Trump urging Republican-controlled states to redraw their lines and was supercharged by a recent Supreme Court ruling severely weakening the Voting Rights Act.Democrats are taking a legal long shot in asking the justices to reverse the Virginia ruling. The Supreme Court tries to avoid second-guessing state courts' interpretations of their own constitutions. In 2023, it turned down a request by North Carolina Republicans to overrule a state Supreme Court decision that blocked the GOP's congressional map.Politically, the appeal could help a party struggling to compete with Republicans in the unusual mid-decade redrawing of congressional boundaries by providing fodder for election-year messaging about a partisan Supreme Court. The court recently allowed Louisiana Republicans to proceed with redistricting after the justices struck down a majority Black district as an unconstitutional racial gerrymander.Related video below: Interactive: Tracking the status of mid-decade redistricting effortsDemocrats have been set on their heels because, days after the Virginia ballot measure passed, the Supreme Court's conservatives reversed decades of rulings and effectively neutered the Voting Rights Act, paving the way for Southern states to eliminate some majority Black districts and pad Republican margins in Congress.The Virginia amendment had been launched long before that ruling. It was intended as a response to Republican gains in Texas, Missouri, North Carolina and Ohio, and to blunt a new map in Florida that just became law. Once the Virginia amendment passed, it briefly turned the nationwide redistricting scramble into a draw between the two parties.That was unraveled by the Virginia Supreme Court's decision. The justices are appointed by the legislature, which has flipped between the two parties in recent decades, and the body is generally not seen as having a clear ideological bent.