The sorting of mail-in ballots is underway in Pennsylvania Tuesday, where thousands of some 3.1 million requested mail ballots were still outstanding as of Monday.
At the Dauphin County Administration Building in Harrisburg, election officials were hard at work sorting and counting what had already arrived.
Voters in Pennsylvania requested nearly 3.1 million mail-in or absent ballots, or more than 10 times the amount received in 2016's election. They had returned slightly over 2.4 million ballots as of Monday morning, according to state data.
Roughly 300 lawsuits have been filed over the election in dozens of states across the country, many involving changes to normal procedures because of the coronavirus pandemic, which has killed more than 230,000 people in the U.S. and sickened more than 9 million.
Pennsylvania, where the candidates appeared to be divided by a razor-thin margin for the state's 20 electoral votes, seemed likely to be the epicenter of any post-election litigation.
The deadline for receiving and counting absentee ballots is Friday under an extension ordered by the state's top court, a ruling that the Supreme Court left in place but suggested it would be open to revisiting.
The majority of mail-in ballots are being cast by Democrats, according to state data. Democrats requested more than 1.9 million ballots by mail, and had returned 1.6 million, according to state data. That means Democrats had yet to return more than 300,000 ballots, according to the latest state data.
With so many voters casting ballots by mail for the first time, Democrats in particular have worried that ballot irregularities — like forgetting to sign it or not putting it inside a second "secrecy" envelope — will result in tens of thousands of votes being disqualified.