Washington(CNN) Pennsylvania Democratic Senate nominee John Fetterman's campaign has gone to a federal court to try to have Pennsylvania voters' mail-in ballots counted if they weren't signed with a valid date.
The question of whether mailed ballots with incorrect or missing dates can be counted is one of the hottest voting disputes in the pivotal state leading up to Election Day, and a divided Pennsylvania Supreme Court recently ordered counties to refrain from counting mailed ballots with missing or invalid dates on their outer envelopes.
But Fetterman and voters his campaign has aligned with are hoping the federal court will supersede the state court's decision.
"The Date Instruction imposes unnecessary hurdles that eligible Pennsylvanians must clear to exercise their most fundamental right, resulting in otherwise valid votes being arbitrarily rejected without any reciprocal benefit to the Commonwealth," attorneys for Fetterman and the Democrats wrote in their new lawsuit filed Monday in the US District Court for the Western District of Pennsylvania.
"The date on a mail ballot envelope thus has no bearing on a voter's qualifications and serves no purpose other than to erect barriers to qualified voters exercising their fundamental constitutional right to vote. This unnecessary impediment violates the Civil Rights Act and the First and Fourteenth Amendments to the U.S. Constitution," they wrote.
Republicans have advocated for strict rules around mailed-in voting that would force ballots with missing information to be rejected.
The Fetterman campaign is joined in its lawsuit by the Democratic Senatorial Campaign Committee and the Democratic Congressional Campaign Committee.
"As we fight this latest Republican attack on Americans' democratic rights, Pennsylvanians should check their ballot status to ensure their vote is counted. We are committed to using every tool at our disposal to protect Pennsylvanians' constitutional right to participate in this election, including defeating the GOP in court," the groups said in a joint statement.
Fetterman's race against Republican nominee Mehmet Oz is one of the year's marquee Senate races.
Republicans view holding on to the seat of retiring GOP Sen. Pat Toomey as key to their hopes of capturing the Senate majority, while Democrats see flipping seats in Pennsylvania and Wisconsin, both states carried by now-President Joe Biden in 2020, as the best way to gird against losses elsewhere.
Earlier Monday, a judge in Monroe County in Northeast Pennsylvania decided that election officials could notify the few hundred voters there whose mail-in ballots were submitted with errors, to give them a chance to correct them.
The judge, Arthur Zulick, noted that the Pennsylvania Supreme Court hadn't gone as far as to say whether ballots with missing dates should be thrown out entirely, or could be corrected by Election Day.
The area's Republican Party had sued to prevent the voter outreach. The case was one of the latest standoffs at the local level in Pennsylvania interpreting how to handle defective mailed-in ballots.
Voters in the county who sent in ballots without secrecy envelopes, external signatures or dates will still be able to vote. Once they are notified their vote may be canceled, they will be given the chance to correct their ballots by 8 p.m. on Election Day.
Zulick noted that the Republicans who brought the case said at a hearing that they had no issue with voters correcting defective ballots if they were handing a ballot over in person, "across the counter."
"The only difference here is that the [Monroe County elections office] emailed or called the voters to advise them of the defect in their ballots," the judge wrote. "I do not find that there was fraud involved or that there was political partisanship undertaken by [Monroe County elections] staff or the Board."