A federal appeals court has ruled that mail-in ballots that have missing or incorrectly written dates on the outer envelope should not be counted in Pennsylvania. The decision strikes down a lower court ruling, which found that the ballot envelope date requirement is a violation of civil rights law.

The Republican National Committee calls it a "crucial victory for election integrity and voter confidence." The ACLU is warning the decision could mean thousands of votes in Pennsylvania won't be counted because of a "meaningless error." The group is considering taking the fight to the U.S. Supreme Court.

Democrats have been far more likely to cast ballots by mail than Republicans in the state since mail-in voting was expanded five years ago.

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