As we enter the last week of campaigning, Pennsylvania has gained huge significance for both sides. It's the new Florida - likely to shape the outcome of the whole race.
No wonder the President is criss-crossing the state today, hoping to erode Joe Biden's clear lead here.
Donald Trump won Pennsylvania by just 44,000 votes in 2016 out of 6 million votes cast, a fraction of one percent. It was a colossal shock to Democrats who thought the urban bulwarks of Philadelphia and Pittsburgh made it secure.
But this is more than about numbers. It's personal.
ITV News Correspondent Emma Murphy reports on the stark contrast between Trump and Biden campaigns as election day nears
Joe Biden was born in Scranton, Pennsylvania. He didn't stay for long, but his political pitch is based on the claim that he speaks the same language as white, working class, union-supporting folk in suburban and rural Pennsylvania.
"I'm one of you," Biden likes to say. "Don't trust the brash New York property-dealer; trust the boy from Scranton."
The political logic is also clear. If Trump loses Pennsylvania's 20 Electoral College votes, he's in a world of trouble on election night. He would then have to win Florida, Michigan, and Wisconsin to see a clear path to victory. These are states he won four years ago, but where he is now struggling.
Team Biden is refusing to show any complacency. As my smart colleague Emma Murphy pointed out - she is covering the Biden campaign - his strategists are haunted by the memory of 2016.
They are refusing to even entertain the idea that this election is in the bag.
But the chances of Biden winning big are growing by the day, despite the candidate's ultra-cautious, low-profile campaigning. And they are eyeing an ever-growing electoral map.
The Democrats sense they have a real chance in Georgia. They are also salivating at the prospect of winning Texas and its giant haul of 38 Electoral College votes - nearly twice Pennsylvania's total.
Why is Joe Biden so keen to win Texas and Georgia when he needs neither?
There is a simple reason. It goes to the heart of the political drama here for the next ten days.
If this election is close, Donald Trump will contest the result and claim that Democrats cheated their way to victory.
But if Biden can win Pennsylvania, Florida and Georgia - and even Texas - then Trump will find it impossible to question the outcome.
At that point it's game over for the President. And the kid from Scranton - 67 years after he left the town - can measure the curtains for the Oval Office.