Pennsylvania’s Supreme Court unanimously ruled Tuesday that mail-in or absentee ballots lacking a date on their return envelopes are invalid, the decision coming days before the midterm elections in the closely watched state.

The Republican National Committee (RNC), National Republican Congressional Committee (NRCC) and the Pennsylvania GOP sued the state in October arguing the state was illegally planning on counting undated and incorrectly mailed in ballots. The suit argued undated ballots could not be counted since state law requires the ballots to be dated.

The Supreme Court recently ruled, however, that a May 2022 decision by the 3rd U.S. Circuit Court of Appeals that found undated ballots must be counted was moot and said authorities should follow established election laws.

But acting Secretary of State Leigh Chapman said following the high court’s decision that officials should keep counting improper ballots, Fox News reported.

“Every county is expected to include updated ballots in their official returns for the Nov. 8 election, consistent with the Department of State’s guidance,” Chapman wrote. “That guidance followed the most recent ruling of the Pennsylvania Commonwealth Court holding that both Pennsylvania and federal law prohibit excluding legal votes because the voter omitted an irrelevant date on the ballot return envelope.”

Every county is expected to include undated ballots in their official returns for the Nov election, consistent with guidance & @CommCtofPA decision. Today’s order from SCOTUS vacating Third Circuit’s judgment on mootness grounds does not affect the prior decision of @CommCtofPA. pic.twitter.com/eDiYpvLZYV

— PA Department of State (@PAStateDept) October 11, 2022

But the state’s Supreme Court ruled Tuesday ballots improperly returned can not be counted, a move met with praise from Republicans. (RELATED: Americans Won’t Know Who Holds The Senate The Day After The Midterms)

“This ruling is a massive victory for Pennsylvania voters and the rule of law,” RNC Chairwoman Ronna McDaniel said in a statement. “Pennsylvania’s Supreme Court has made clear that incorrectly dated and undated mail ballots can not be counted. Republicans went to court, and now Democrats and all counties have to follow the law: this is a milestone in Republicans’ ongoing efforts to make it easier to vote and harder to cheat in Pennsylvania and nationwide.”

Jason Snead, the executive director of Honest Elections Project, said the “straightforward rule helps to stop late and illegal voting without burdening anyone’s right to vote.”

“Despite the black-and-white legal requirement, the Pennsylvania Acting Secretary of State tried to ignore the law and count undated ballots,” Snead said.