There is disagreement between state Republicans and Democrats over whether a mail-in ballot should be rejected if the signature does not match signatures in permanent voter registration records.
Secretary of State Kathy Boockvar claimed that signature discrepancies should not be cause for rejecting the ballots, and petitioned the state Supreme Court to weigh in.
Without a ruling, there is a concern that some ballots could be rejected at the county level, and voters disenfranchised.
However, Republicans are worried about ensuring the security of the election and protecting the process from potential fraud.
It has been reported that about 26,500 ballots were rejected during the June primaries due to apparent signature defects.
Around 2.5 million Pennsylvanians are expected to vote by mail this election cycle – with more Democrats than Republicans expected to do so.
The signature squabble is the latest in a string of election-related disagreements in Pennsylvania – a key swing state – that have found their way into the court system.
Democrats and Republicans in the state are battling over whether to extend the mail-in ballot counting window past Election Day.
The Pennsylvania Supreme Court also said that if voters do not place their ballot in a “secrecy” envelope their votes would not count.