PHILADELPHIA — Pennsylvania Democrats are growing increasingly confident that when all the votes are counted, Joseph R. Biden Jr. will have a significant lead of more than 100,000 votes.
At a news conference Thursday morning in Philadelphia, Sharif Street, a state senator and vice chair of the Pennsylvania Democratic Party, said that the party thinks Mr. Biden could win by as much as 190,000 votes in the state, driven in large part by the number of votes still being counted in Philadelphia.
City election officials have not provided an update as to when they will finish counting ballots, but the collar counties around Philadelphia, including Bucks County and Montgomery County, are getting closer to a full count.
Workers spent the night tallying a backlog of more than one million absentee and mail-in votes, and state officials said they expected a clearer picture to emerge with the release of more results. Mr. Biden trailed Mr. Trump by about 115,000 votes as of 12:30 p.m. Eastern on Thursday.
Winning Pennsylvania’s 20 electoral votes would clinch the election for Mr. Biden, who used his Scranton roots in an appeal to win back the once-blue state that broke for Mr. Trump in 2016. Mr. Trump has aggressively challenged voting procedures in the state and is suing to halt the counting of ballots that were cast before the deadline, among other legal challenges.
Gov. Tom Wolf, a Democrat, condemned the legal maneuvers.
“Our election officials at the state and local level should be free to do their jobs without intimidation or attacks,” Mr. Wolf said in a statement. “These attempts to subvert the democratic process are disgraceful.”
Mr. Biden is expected to gain significant ground in Philadelphia and its suburbs, where vote counters were working around the clock to sort through hundreds of thousands of uncounted votes. A number of ballots also remain in more conservative counties, giving the Trump campaign hope.
If the race comes down to the wire, the fate of thousands of provisional ballots set to be counted next week might also be in play. Many voters who requested mail-in ballots but decided to vote in person instead and did not bring their mail ballots with them to be “spoiled,” or rendered unusable, were given provisional ballots, said Bethany Hallam, a member of the elections board of Allegheny County. At least one Republican lawsuit was filed to throw out certain provisional ballots, and Ms. Hallam expects more are coming.
Mr. Trump “sent his entire legal team to Pennsylvania to try to invalidate legal votes in whatever way possible,” Ms. Hallam said.
On Thursday, the Trump campaign held a brief news conference outside the Convention Center, celebrating a court order that allowed for their observers to more closely watch the ballot counting in Philadelphia.
City officials quickly filed an appeal to the Pennsylvania Supreme Court, which resulted in a brief pause in the count in Philadelphia. But it was quickly resumed. The state Supreme Court has not issued a decision as to whether they would accept or deny the appeal.