BREAKING: Pennsylvania Supreme Court rules that mail-in ballots that are undated and misdated will NOT be counted in the 2024 election.

The development, which is a huge win for Republicans, is expected to impact thousands of votes in November.

The PA Supreme Court vacated a Commonwealth Court ruling, saying they "lacked subject matter jurisdiction to review the matter."

"The Commonwealth Court lacked subject matter jurisdiction to review the matter given the failure to name the county boards of elections of all 67 counties," the court wrote.

"This is a huge win to protect the vote in Pennsylvania that will protect commonsense mail ballot safeguards and help voters cast their ballots with confidence. The Keystone State will be absolutely critical in this election, and the Supreme Court has decided a major victory for election integrity," RNC Chairman Michael Whatley said.