HARRISBURG, Pa. (AP) — A new lawsuit is trying to prevent thousands of mail-in ballots from being thrown out in the November election in Pennsylvania. The battleground state is expected to play a critical role in selecting a new president. The lawsuit filed Tuesday by left-leaning groups is the latest of several cases to challenge a provision in Pennsylvania law that voters must write the date when they sign their mail-in ballot envelope. Voters not understanding that provision has meant tens of thousands of ballots have been thrown out since 2019. The latest lawsuit says a voter-written date is meaningless and that rejecting someone’s ballot over it should violate Pennsylvania’s Constitution.