WASHINGTON — Former Vice President Joe Biden launched his campaign for president Thursday as the Democratic front runner — but that status can be precarious.

Just ask Jeb Bush in 2016, or Hillary Clinton in 2008.

Like those early favorites who later faded, Biden entered this race with a mighty political legacy and support from establishment figures who hailed him as their party’s safest bet to win the White House. But recent history suggests that those traditional advantages will mean little unless Biden proves he can connect with a restive and changing Democratic coalition.

Biden’s initial pitch centered on the man so many Democrats despise, President Donald Trump.

Citing the president’s equivocation after a 2017 white supremacist rally in Charlottesville, Va., Biden decried a "threat to this nation ... unlike any I had ever seen in my lifetime.”

"If we give Donald Trump eight years in the White House, he will forever and fundamentally alter the character of this nation, who we are, and I cannot stand by and watch that happen,” Biden said.

The direct shot at Trump, and Biden’s argument that he would be a stabilizing force, contrasted sharply with most of his Democratic competitors, who have spent months asserting that the party should focus on its own vision for middle-class Americans.

The Scranton-born Biden also signaled a heavy focus on Pennsylvania, one of the most critical swing states and a virtual must-win for Democrats — and a place where Democrats have long treated Biden as one of their own. He plans to lay out the other core elements of his campaign in rallies in Pittsburgh on Monday and in Philadelphia on May 18. In between, he plans to visit Iowa, South Carolina, Nevada, and New Hampshire.

On Thursday afternoon, Biden, in shirtsleeves and Ray-Ban aviators, visited Gianni’s Pizza in Wilmington, where he shook hands with customers and ordered a pepperoni pie. The owner said Biden used to visit with his now-deceased son, Beau, before he became vice president.

Asked for his message to the world, Biden said, “America’s coming back like we used to be. Ethical. Straight. Telling the truth."

Biden supporters argue that his blue-collar roots and association with former President Barack Obama can unite Democrats and win back the white working-class voters who defected to Trump in 2016. But parts of his nearly 50-year public record, including past stances on race and crime, his treatment of women, and his ties with Delaware’s sizable financial-services industry, may appear too dated or too moderate for the current party. An Obama spokesperson offered words of praise Thursday, saying the two men have “a special bond,” but stopped short of an endorsement.

Biden’s first major public event will be at a Pittsburgh union hall Monday, but first his allies put on a high-dollar fundraiser hosted by Comcast senior executive vice president David L. Cohen in Philadelphia on Thursday.

“Welcome to the race Sleepy Joe,” Trump tweeted. “I only hope you have the intelligence, long in doubt, to wage a successful primary campaign. It will be nasty — you will be dealing with people who truly have some very sick & demented ideas."

Biden joins the contest powered by near-universal name recognition, a positive image among Democrats, and consistent leads in early primary polls.

A good ‘sidekick.’ But a good president?

He will be tested, however, by rivals representing all corners of the Democratic coalition, including women and people of color, some of them decades younger (he is 76), as he seeks to ignite his party’s base in ways that Jeb Bush and Hillary Clinton failed to do. Each was swamped by newer faces who connected on a visceral level.

The similarly sprawling 2016 GOP primary offers two potential parallels for Biden.

Trump, the most recognizable candidate that year, rose to the top early and never relinquished his lead. Bush, the former Florida governor, started as the insider pick, but found himself wildly out of step with the grassroots GOP electorate.

Biden will have to prove he’s more than just a familiar name, said Mike Murphy, a Republican consultant who ran Bush’s 2016 Super PAC.

“Biden’s going to have to go out and make a case,” said Murphy, co-director of the University of Southern California’s Center for the Political Future. “We know he’s been a good sidekick, but will he be a good president? Or is he just going to be ‘good ol’ Joe’? I don’t think good ol’ Joe is going to be enough to win this primary.”

Joe Biden speaks at the International Brotherhood of Electrical Workers construction and maintenance conference in Washington earlier this month.
Manuel Balce Ceneta / AP
Joe Biden speaks at the International Brotherhood of Electrical Workers construction and maintenance conference in Washington earlier this month.

But if Biden presents himself as a fighter to take on Trump, he said, “that’s something to work with.”

>> READ MORE: For some 2020 Democrats, incrementalism is out. Bold liberal ideas are in. They come with risks.

Lara Brown, a political science professor at George Washington University, said the opening salvo against Trump might help the more moderate Biden connect with Democratic activists.

“All the other candidates are trying to offer a vision for the future,” Brown said. “But Biden is saying, you can’t get to the future unless we take on this fight.”

A head start

Biden is in some ways better off than Jeb Bush was.

Democrats like him far better than Republicans liked Bush, and with polls showing that the party’s voters prize most the ability to beat Trump, Biden allies stressed that he is the candidate who can win back vital Rust Belt states such as Pennsylvania, Michigan, Wisconsin, and Ohio.

“His views make him, I think, in the fall, the most electable Democratic candidate,” former Gov. Ed Rendell said in a March interview. “That’s more important than any stance on any ideology.”

A Morning Consult/Politico poll released Wednesday showed Biden leading Trump in a head-to-head race, 42 percent to 34.

Biden has foreshadowed his campaign for months, emphasizing his roots in a working-class town in Northeastern Pennsylvania and the need to return to a more civilized era in politics.

Sen. Bob Casey (D., Pa.), a fellow Scranton native, immediately endorsed Biden on Thursday, along with several other Democratic senators, including Delaware’s Chris Coons and Tom Carper.

Harold Schaitberger, president of the International Association of Fire Fighters, described Biden as a Democrat who can speak to “everybody that works a job that has to go home and wash their hands and take a shower after work. Those are the voters I believe that to some degree abandoned the party in 2016.”

The former Delaware senator also boasts more international experience than anyone in the field, thanks to more than 30 years on the Senate Foreign Relations Committee and his eight in the White House.

Past failures, new scrutiny

In entering one more race, Biden could cap his career with the nation’s highest office, but risks the goodwill and popularity he has established.

He flopped in two previous presidential runs, and will face questions about whether he is too old for a grueling campaign and the presidency. He first entered public life in 1970 and joined the Senate in 1972, and now seeks to lead a party in which some of its most vocal factions are demanding bold and fresh voices, including some who want to elevate women, non-white leaders, or younger people who represent the party’s diversity. Activists are calling for dramatic proposals to confront what they view as crises on health care and climate change.

“The old guard of the Democratic Party failed to stop Trump, and they can’t be counted on to lead the fight against his divide-and-conquer politics of today," said a statement from Alexandra Rojas, executive director of the liberal Justice Democrats.

Some have decried the wealthy, powerful donors paying to attend Thursday’s event in Philadelphia, though Biden’s camp has said he will not take donations from corporations, their political committees, or lobbyists.

As the #MeToo movement against sexual harassment has reshaped politics and culture, some of Biden’s behavior as a hands-on campaigner has also been viewed in a more critical light.

In late March, Lucy Flores, a Democrat who ran for lieutenant governor of Nevada, wrote an essay accusing Biden of making her feel “uneasy, gross and confused” when he smelled her hair and kissed the back of her head at a 2014 campaign event. Earlier this month Biden released a video in which he acknowledged that “the boundaries of protecting personal space have been reset. I get it. I get it.”

Biden also presided over a 1991 Senate hearing at which an all-male panel sharply questioned Anita Hill after she accused Clarence Thomas, then a Supreme Court nominee, of sexual harassment. The former vice president said in March that “to this day, I regret I couldn’t give her the kind of hearing she deserved.”

And he once opposed school busing meant to help integrate schools in the 1970s, and supported a 1990s crime bill blamed for targeting minorities.

Biden’s supporters have been encouraged that his polling has remained relatively strong, despite such scrutiny. The attention, though, is about to be magnified.