HARRISBURG, Pa. (AP) — Some of Pennsylvania’s largest counties scrambled Monday to help voters fix mail-in ballots that have fatal flaws such as incorrect dates or missing signatures on the envelopes used to send them in, bringing about confusion and legal challenges in the battleground state on the eve of the election. Elections officials in Philadelphia and Allegheny County, which includes Pittsburgh, announced measures they were taking in response to state Supreme Court rulings in recent days that said mail-in ballots may not be counted if they lack accurate handwritten dates on the exterior envelopes. Ahead of Tuesday’s midterms, more than a million mail-in and absentee ballots have already been returned in Pennsylvania, with Democrats far more likely than Republicans to vote by mail. The numbers are large enough that they might matter in a close race, such as the contest between Democrat John Fetterman and Republican Mehmet Oz that could determine majority control of the U.S. Senate. The Department of State said it was unclear just how many ballots are at issue across the state. The agency over the weekend asked counties to provide the numbers, broken down by political party. Officials said some counties were not letting voters fix their mistakes. A new federal lawsuit over the envelope dates was filed Monday in Pittsburgh federal court by the national congressional and senatorial Democratic campaign organizations, two Democratic voters and Fetterman’s U.S. Senate campaign. They sued county boards of election across the state, arguing that throwing out ballots that lack proper envelope dates would violate a provision in the 1964 U.S. Civil Rights Act that says people can’t be kept from voting based on what the lawsuit calls “needless technical requirements.” A separate federal lawsuit filed Friday makes a similar argument.