For much of the 2024 campaign, President Joe Biden could easily see himself taking the stage at the Democratic National Convention to accept the party’s nomination — a victory lap as he sought a second term in the White House.

But now, Biden’s prime-time speech in Chicago on Monday night will mark a bittersweet moment for his legacy and for the party.

It comes after a rapid shuffle catapulted Vice President Kamala Harris to the top of the ticket as Biden exited the race amid Democrats’ concerns about his age and ability to campaign reached a boiling point.

“This is extraordinary in a lot of ways in politics because sitting presidents don’t often turn over the reins,” said Jim Kessler, co-founder of the center-left think tank Third Way.

The scene will be a study in political contrasts, he says.

“In a way, it feels like a Hall of Fame athlete that’s making the tour to stadiums in the final season. But it’s also a torch passing and the Harris campaign is about the future,” Kessler said. “The needle I expect Biden will thread is celebrating the past and focusing on the future.”

Biden is slated to speak on the opening night of what will be a four-day gathering of prominent Democrats from across the nation culminating in Harris and her running mate Gov. Tim Walz celebrating her history-making rise to become the party’s nominee.

Asked by a reporter on Sunday how he was feeling about his Monday night keynote, he responded, “Good, real good.”

The White House said last week Biden was looking forward to addressing not only Democrats but the nation about what’s at stake this election and to call for unity.

“He understands this is an incredibly important moment,” White House press secretary Karine Jean-Pierre told reporters. “He’s still very much the leader of the party, right? And he takes that very seriously. And he’s also very proud of his vice president.”

First lady Jill Biden, his strongest advocate, will speak before him, and afterward the couple heads to California, not planning to stay for Harris’ speech Thursday night.

Biden endorsed Harris minutes after he announced he would no longer run for reelection. At their first joint appearance since then, an event last Thursday to tout lower prescription drug prices, Biden said she would make “one hell of a president” as he was met by the crowd with chants of “Thank you, Joe!” — a rallying call that could very well emerge at the DNC.

But the road from his poor debate performance against Donald Trump in late June to his bowing out of the race was rocky, as he initially remained defiant against calls for him to step aside. With a growing drumbeat of Democratic lawmakers publicly urging him to drop out, private pressure from Democratic leaders such as Nancy Pelosi and polls showing the gap between he and Trump widening, Biden officially withdrew on July 21.

“All signs pointed to him wanting to have delivered that acceptance speech but the road was closed by funders, by the public, by the media, by key power brokers within the party, and so he’s having to switch up and it’s awkward,” said William Howell, an American politics professor at the University of Chicago.

Still, observers expect Biden to receive a resounding hero’s welcome at the convention.

“There will certainly be some callouts to his accomplishments, which aren’t trivial,” Howell said.

Biden is likely to tout some of his policy achievements, including the Inflation Reduction Act, which led to Medicare price negotiations and climate change investments; the Bipartisan Safer Communities Act, the first major piece of federal gun reform in decades; and the Infrastructure Investment and Jobs Act, which included $550 billion in new spending for highways, bridges, public transit and more.

“He will paint himself as a unique president that served at a time when the nation needed someone who could stabilize the important institutions and who was able to get things done inside these institutions that are often strained because of partisanship,” said Brandon Rottinghaus, a professor of political science at the University of Houston who focuses on the presidency.

“He has a record that would reelect an incumbent,” said Kessler. “What stood in the way was voters concerned about his age.”

Kessler added, “There’s a luxury to giving a speech when you don’t have to convince voters to vote for you. So there’s an aspect to his address on Monday that’s freeing.”

But much of Biden’s legacy may rest on what happens with the Democratic Party going forward, starting with Harris’ candidacy.

In an Oval Office address explaining his 2024 decision, Biden said that personal ambition couldn’t get in the way of saving democracy and that it was time to usher in the next generation.

“In 2024, he stepped aside so that she and the party could succeed. That magnanimous act is only complete if it’s fully successful,” Rottinghaus said. “Harris winning would be a legacy-defining moment for a president who said that he was going to be a bridge between the past and the future.”