Biden Will Set 2024’s Soaring Stakes in His Beloved, Divided Pennsylvania

President Biden is returning to the battleground state of Pennsylvania on Friday to try to define the 2024 presidential election as an urgent and intensifying fight for American democracy.

Mr. Biden is expected to use a location near the famous Revolutionary War encampment of Valley Forge and the looming anniversary of the Jan. 6 Capitol riot to cast preserving democracy as a foundational issue to the 2024 campaign, according to a senior Biden aide who spoke on the condition of anonymity to preview the remarks.

The address, which builds on previous speeches about safeguarding American institutions and combating political violence, represents a bet that many Americans remain shaken by the Jan. 6 attack and Donald J. Trump’s role in it.

Leaning on a phrase used by America’s first president, George Washington, around the time he commanded troops at Valley Forge, Mr. Biden is expected to suggest that the 2024 election is a test of whether democracy is still a “sacred cause” in the nation, the aide said.

Mr. Biden is fond of using sites of historical significance to underscore speeches that he and his team see as important moments. He traveled to Independence Hall in Philadelphia before the midterm elections and to Gettysburg, Pa., during the 2020 presidential campaign.

His campaign views the events of Jan. 6 — when Trump supporters stormed the Capitol in a violent culmination of his election denialism — as critical to understanding how the 2024 campaign will unfold. His team notes that Mr. Trump and Republicans have tried to rewrite the history of that day but argues that images of the Capitol riot remain seared in the minds of voters.

But as Mr. Biden heads again to Pennsylvania — the state of his birth, a part of his blue-collar political identity and the startlingly frequent backdrop of his public appearances — there are signs that he needs to shore up the coalition that elevated him and rejected Mr. Trump in 2020.

Early polling shows weakness among important constituencies including nonwhite and younger voters, and many Americans worry about his age. New York Times/Siena College polling from the fall found Mr. Biden, 81, trailing Mr. Trump, the 77-year-old front-runner for the Republican nomination, in five of six key battleground states, including Pennsylvania.

The Biden campaign said the crowd on Friday would include young people who were motivated to get involved in politics by the events of Jan. 6, as well as some elected officials who have been directly affected by election denialism. The visit will be Mr. Biden’s 31st to Pennsylvania since taking office, according to his campaign.

Mr. Trump, who faces significant legal peril including two trials this month, is set to campaign on Friday in Iowa, which will hold the first Republican nominating contest on Jan. 15.

“Democrats are confident in what President Biden, Vice President Harris, have done over the last four years,” said Lt. Gov. Austin Davis, a Pennsylvania Democrat. “We’re also nervous and anxious to really get started in earnest. We all know that this is going to be a close race, this is going to be a close campaign and we can’t leave anything up to chance.”

Some Democrats worry that the Biden campaign has been slow to build in their states, or to articulate a vision for a second term.

Mr. Biden’s team argues that there is plenty of time to engage voters, many of whom are not yet focused on an election 10 months away.

“We look forward to scaling our efforts across the board to mobilize our coalition, including speaking to them more about how a second Biden-Harris term will deliver on important issues for them at the right moment to maximize impact,” Kevin Munoz, a Biden campaign spokesman, said in a statement.

Mr. Biden’s team has framed the Friday speech as an opening salvo to the 2024 contest and a moment to highlight the stakes. The campaign, which says it is ramping up its organizing efforts, has also released its first television ad of the year, focused on the preservation of democracy and combating political violence and extremism.

“All of us are being asked right now, what will we do to maintain our democracy?” Mr. Biden says in the spot. “History’s watching. The world is watching.”

And as he warns against political extremism and violence, he is expected to appear on Monday at Emanuel African Methodist Episcopal Church, a historic Black church in Charleston, S.C., where a white supremacist killed nine parishioners in 2015.

Mr. Biden plainly feels particular affection for both states. Black voters in South Carolina revived his nearly moribund 2020 presidential bid and propelled him to the Democrats’ nomination.

And he won Pennsylvania that fall — flipping it back after Mr. Trump became the first Republican presidential nominee to carry the state in nearly three decades — in part by tapping into his roots in Scranton, Pa.

“Mr. Biden shows that he’s a common man,” said George C. Brown, the mayor of nearby Wilkes-Barre, Pa., and a Biden supporter. “People can relate to him.”

Mr. Biden has returned to the state — and in particular, the Philadelphia area — again and again for major speeches, including one about threats to democracy before the 2022 midterm elections.

Asked about Mr. Biden’s focus on that issue, Mr. Davis, the lieutenant governor, emphasized the need for a forward-looking message.

“It’ll be an important factor of this cycle, but I also think it’s going to have to be coupled with a clear vision for how we’re going to improve the lives of working families,” he said. “I don’t necessarily think it will have the same influence that it had four years ago, given where we are in time, but I think it’s definitely a part of the message that the president should deliver, in addition to what his vision for a second term will be.”