HARRISBURG, Pennsylvania -- Pennsylvania's staking its claim as center of the political universe this weekend as presidents past and present campaign for their candidates ahead of midterms Election Day.
President Joe Biden and former President Barack Obama teamed up Saturday to stump for Democratic gubernatorial candidate Josh Shapiro and Senate candidate John Fetterman in Philadelphia.
"This crowd is so loud I think they can hear us in Latrobe," Biden said in his opening remarks, taking a swing at former President Donald Trump's rally there later Saturday night. "They're going to hear us on Tuesday."
"The power to shape that outcome is in your hands," Biden said. "Two years ago, you used your power not only to make Trump a former president, but a defeated president."
Trump held a rally at Arnold Palmer Regional Airport in support of Republican gubernatorial candidate Doug Mastriano and Senate candidate Dr. Mehmet Oz, calling them both "great people."
"You're going to elect the incredible slate of true America-first Republicans up and down the ballot," Trump said. On the Biden and Obama event at Temple University, Trump said, "I heard they had a little rally."
"They don't call it the Keystone State for nothing," said David Dix, a Philadelphia-based political strategist who has worked on Republican and Democratic campaigns, about the 11th-hour attention from both sides. "Once again, Pennsylvania is the political epicenter of the country and the balance of the House and Senate weigh from here on Tuesday."
"It's just another indicator that we are a deep purple state that makes up our mind late and oftentimes does split the ticket among Democrats and Republicans," Dix added.
Pennsylvania's marquee Senate race could determine which party wins control of the chamber. Republicans need to gain just one seat to become the majority, as Democrats currently control the 50-50 Senate with Vice President Kamala Harris acting as the tie-breaker.
"That race has been on the razor's edge for a long time," said Christopher Nicholas, a longtime Republican strategist in Pennsylvania.
The margin between Fetterman and Oz is getting tighter by the day, according to FiveThirtyEight's polling average, with the two candidates separated by just 0.4 percentage points.
"There's no quit in John Fetterman," Biden said Saturday. "There's no quit in Pennsylvania. There's no quit in America, we just have to remember who we are, we are the United States of America."
Biden also took a shot at Oz, who was criticized for living in New Jersey until late 2020: "I've lived in Pennsylvania longer than Oz has lived in Pennsylvania, and I moved when I was 10 years old," Biden said.
In a message to voters on Saturday, Fetterman pitched himself as a lifelong public servant while accusing Oz of trying to "use" Pennsylvania and attempting to buy the seat.
Oz, in a closing pitch at a rally in Elizabethtown earlier this week, described himself as an agent of change and encouraged attendees to tell neighbors about his message on the economy, crime and the border.
"There are three topics that I have spent my campaign dwelling on," he said. "They are the kitchen table issues that every family in Pennsylvania has talked about."
The gubernatorial race between Shapiro and Mastriano is another contentious race, and one of the biggest tests of Trump's election denialism on the ballot this cycle.
Mastriano, a Republican state legislator, attended Trump's Jan. 6 rally just before the Capitol attack and has continued to spread the former president's lies about the 2020 election results.
FiveThirtyEight's polling average shows Mastriano behind in the race by roughly 10 percentage points.
Biden's campaigned heavily in Pennsylvania this year, and in this final stop in Philadelphia he and Obama aimed to boost Democratic enthusiasm in a key area of the state. Obama, citing his own midterm losses in 2010, told rally-goers to make sure their friends vote.
"Democrats view it as crucial to get as high a turnout as possible in the city, especially among the Black community" said Nicholas. "That's always the target for them."
Biden's success in the Democratic strongholds Philadelphia and Pittsburgh, and their neighboring suburbs, ultimately led to his win there in 2020 over Trump.
Trump last visited Pennsylvania in September, when he held a rally for Oz and Mastriano in Wilkes-Barre. The stakes are high for the former president, who is laying the groundwork for a 2024 campaign and could make an announcement as soon as the week of Nov. 14, according to sources.
"Latrobe is essentially the epicenter of Republican turnout," Dix said, noting nearby Allegheny County probably has more registered Republicans "than anywhere else in the state."
"I certainly understand the strategy and why the former president decided to rally there," Dix said.
- ABC News' Will McDuffie contributed to this report.