They’ve been shadow boxing at various campaign stations across the United States for weeks, but Democratic and Republican leaders find themselves on the same battlefield Saturday as they hold closing talks in Pennsylvania for next week’s midterm elections.

President Joe Biden will rally alongside his old boss, Barack Obama, as Democrats use their big guns to build up the energy they hope will spread across the country and reverse the late polling right swing.

And in a split-screen preview of a possible re-run of the 2020 presidential campaign, the Midwestern state is also hosting Biden’s predecessor and bitter political rival Donald Trump.

Obama — still the party’s most bankable star six years after leaving the White House — begins the day in Pittsburgh with Democratic nominee John Fetterman dead heat to Republican television medic Mehmet Oz in their crucial Senate race.

Biden and Obama then appear in Philadelphia, the historic cradle of US independence, where the 44th and 46th Presidents will court suburban voters who form a crucial base of Democratic support.

Keystone State backed Trump over Hillary Clinton for president in 2016 but preferred Biden over Trump in 2020.

Strategists from both parties believe the side that wins the post of resigning Republican Pat Toomey will hold a majority in the upper chamber of Congress next year.

Fetterman and Oz fought for an hour in the state capital of Harrisburg 10 days ago, with Fetterman still grappling with communication issues after a stroke in May derailed his campaign.

“The month-to-month shifts in support for Oz are not statistically significant,” said Patrick Murray, director of Monmouth University’s Independent Polling Institute.

“The general trend is that he clashed with some voters who weren’t entirely comfortable with him, but that was mostly pre-debate.”

Just a few miles east of Pittsburgh in Latrobe, Trump — the 45th president with one term in office and aspirations to return as the 47th — will seek to cement support in a region that gave him wide margins in 2016 and 2020.

Pennsylvania holds not only for control of the Senate, but also for the balance of power among the state’s 50 governors, influential officials who influence most aspects of voters’ lives, from education and health care to voting rights.

Democratic gubernatorial candidate Josh Shapiro has spotlighted the fringe views of Senator Doug Mastriano, his far-right opponent who was involved in Trump’s attempts to overthrow the 2020 election.

A victory for Trump-backed Mastriano would give the prominent electoral denier control of the state’s voting system for the 2024 presidential election.

Like Biden, Trump has visited Pennsylvania twice this year, most recently gathering for Oz and Mastriano in Wilkes-Barre in early September.

The 76-year-old tycoon has previously unsubstantiated claims that the state’s elections were “rigged” and repeated his false claims that his own 2020 defeat was the result of widespread fraud.

“As Biden’s approval rating plummets, Pennsylvania crime rises and Pennsylvanians grapple with a 74 percent increase in heating oil use coupled with record inflation just weeks before winter,” Trump’s office said in a statement.

“The America First Movement offers the Keystone State an alternative vision for America: safe roads, cheap gas, low inflation and a prosperous American economy.”