Georgia’s highest court on Monday ruled that thousands of Cobb County voters who received their ballots late will not have their votes immediately counted if their ballots are received by officials after Election Day, a decision that sided with national Republicans.

The Georgia Supreme Court said that those ballots, which Cobb County officials admitted they failed to ship out on time, must be set aside pending further litigation if they aren’t returned by Tuesday at 7 p.m., the deadline under existing state law and the time polls close in the state.

A Cobb County judge previously extended the deadline until 5 p.m. on Friday — the same receipt deadline for uniformed and overseas voters — as long as the ballots were postmarked by the close of polls on Election Day.

The Republican National Committee (RNC) and Georgia Republican Party appealed that decision directly to the state’s highest court, arguing that Georgia law plainly requires that “‘all absentee ballots’ must be ‘returned’ on ‘the day’ of the ‘election.’”

“The Superior Court’s deviation from the Legislature’s instruction is baseless,” lawyers for the state and national Republicans wrote. “The Plaintiffs claim a burden on their right to vote, but the Georgia Constitution does not guarantee a right to vote by mail. Voters still have many options to vote, including by voting in person or delivering their absentee ballots in person.”

Georgia’s American Civil Liberties Union, which brought the initial lawsuit on the behalf of three affected voters, urged other affected voters to instead cast their ballots in person or deliver their absentee ballots by hand to county election officials by the updated deadline.

“If neither is an option, we urge voters to immediately send their ballot back to the county via overnight delivery, if possible. Only as a last resort, should voters simply mail their ballots,” the group said in a press release. “Unfortunately, there are voters who will not be able to access the remaining options and will not have their voices heard in this election as a result of this ruling.”

The Georgia Supreme Court ordered the Cobb County Board of Elections and Registration to notify the affected voters of their Election Day deadline by email, text message and a public announcement on the board’s website.

The panel also noted that the ruling does not pertain to voters casting ballots under the federal law for uniformed and overseas absentee voters.

Three of the panel’s nine justices dissented but did not explain why. A fourth justice was disqualified from the case. The other five ruled in the RNC’s favor.

Georgia is a critical battleground state that could help sway the outcome of the presidential election. President Biden beat former President Trump by 14 percentage points in Cobb County in 2020 and ultimately won the state by a narrow margin.

— Updated at 5:34 p.m.