President Trump narrowly won Pennsylvania in 2016. This year, the question is whether big turnout in the Democratic strongholds of Pittsburgh and Philadelphia can deliver his Democratic rival, Joe Biden, a win.
In particular, Philadelphia has been a focus for Trump; four years ago, only 15% of the city's voters picked him. Trump has claimed — with little evidence — that the local election system is corrupt. His critics say the president is trying to suppress turnout in the city.
"A lot of bad things happen there with the counting of the votes," Trump said at a recent campaign stop in Pennsylvania.
There have been issues, including technical hiccups on the first day of early, in-person voting. A laptop used to program voting machines was stolen. A reporter for NPR member station WHYY got inside a warehouse where voting machines are stored, although city officials beefed up security after that.
This election is like no other in Philadelphia — and all across Pennsylvania. A new state law has made it much easier to vote early and by mail. With the pandemic, people signed up in droves, especially Democrats. About a third of the state's 9 million voters planned to cast their ballot by mail, and more than three-quarters of them already had done so by last Friday.
But under state law, counties can't even open those ballots to prepare them for counting until 7 a.m. on Election Day. That's one reason why Philadelphia spent $5 million on new equipment to speedily process the deluge of mail-in ballots.
Philadelphia has turned its sprawling convention center into a mail-in vote-counting factory. One machine sorts returned ballots in hours, instead of days if done manually. Another machine cuts open envelopes and spreads them apart with suction cups so workers can quickly pull out the ballots.
And there are 12 high-speed scanners that process 32,000 ballots an hour.
"Historically, we had to do it all by hand with a scanner gun — individual people sitting at a desk beep-beeping every envelope in," said Lisa Deeley, the chair of the Philadelphia City Commissioners Office.
Deeley won't predict when counting will be finished; state officials say they expect most results will be tallied by Friday.
Meanwhile, President Trump continues to sow doubt about the veracity of voting in Philadelphia. The Trump campaign videotaped people putting ballots in drop boxes. Election groups openly worry that armed Trump supporters may show up to intimidate voters.
That prompted Philadelphia District Attorney Larry Krasner to issue a warning. "Anyone who comes to the cradle of American democracy to try to suppress the vote — and violates the law and commits crimes — is going to find themselves in a jail cell talking to a Philadelphia jury," he said last month.
So far, there have been no reports of voter intimidation. At an early in-person voting office last week, Philadelphians seemed to be taking all of this in stride.
"I don't have any complaints, other than the wait — but what are you gonna do?" said Waverly O'Neal, 19, standing in a line of mask-wearing voters that stretched around the block.
Given Trump's focus on Philadelphia, Pennsylvania's Democratic Gov. Tom Wolf said he believes Trump is trying to reduce voter turnout.
If that's true, it's not working. More than 90% of Philadelphia's voters have registered to vote — the highest number in 35 years.