Republican officials asked the U.S. Supreme Court on Thursday to move up North Carolina’s recently extended deadline for accepting late-arriving absentee ballots postmarked by Election Day.

State Republican legislative leaders argue that the updated deadline, issued in an official memo after early voting had begun, will result in unequal treatment of voters and dilute the value of those who cast ballots before the rule was changed. They also say it usurps legislators’ authority to set the deadline.

State election officials who made the change “are administering the election in an arbitrary and nonuniform manner that will result in disparate treatment by inhibiting the rights of voters who cast their absentee ballots before the Memorandum was issued,” says the appeal filed by lawyers representing state Senate leader Phil Berger and House Speaker Tim Moore, both Republicans.

The North Carolina State Board of Elections had announced in late September that absentee ballots could be accepted by counties until Nov. 12, as long as they were mailed by Nov. 3, which is Election Day. That rule change lengthened the period for accepting ballots from three to nine days after the election.

The state board made the change as part of a legal settlement with a union-affiliated group that had challenged what it saw as restrictive voting rules during the coronavirus pandemic. The settlement said the longer deadline was needed in case of postal delays.

Federal district and appeals courts declined to intervene in the Republicans' lawsuit.

A federal judge considering the deadline and other absentee ballot procedures ruled last week that absentee ballots that arrive without a witness signature can’t be counted. That prompted the state to issue guidance Monday that such voters must start their ballot over and have it witnessed again. The court battle had caused absentee ballots with a range of errors to be set aside for about two weeks while the procedures were debated.

The Supreme Court has already weighed in on another battleground state’s ballot deadline, ruling earlier this week that Pennsylvania could count mailed-in ballots received up to three days after the Nov. 3 election, rejecting a Republican appeal. The high court's Monday ruling upholds a Pennsylvania state Supreme Court decision that ballots may be accepted until Nov. 6, even without a clear postmark, as long as there is no proof they were mailed after the polls closed.

North Carolina is considered another key battleground state where races for the presidency and U.S. Senate are closely contested.