PITTSBURGH — Representative Conor Lamb thinks he knows what it takes for Democrats to win statewide in Pennsylvania.
He looks to President Biden, whose narrow victory in the state — called four days after Election Day — put him over the top and in the White House.
“People will use the word moderate,’’ Mr. Lamb said at his home in Pittsburgh’s South Hills on Thursday. “We’re a swing state. I don’t think we’re too far ideologically one way or the other.’’
On Friday, at a union hall on Pittsburgh’s Hot Metal Street, Mr. Lamb announced his long-expected entry into Pennsylvania’s 2022 Senate race, vowing to “fight for every single vote across our state on every single square inch of ground,” and presenting himself as just middle-of-the-road enough to get elected statewide.
The question is whether he is liberal enough to win the Democratic primary.
A Marine veteran and former prosecutor, Mr. Lamb, 37, is likely the last major candidate to enter what are expected to be competitive, knockdown primary battles in both parties for the seat now held by Senator Pat Toomey, a Republican who is retiring.
It is the only open seat now in Republican hands in a state that Mr. Biden carried, and Democrats see it as their best opportunity to expand their hairbreadth control of the Senate, where the 50-50 partisan split leaves Vice President Kamala Harris to cast deciding votes. A single additional seat would mean a simple Democratic majority in the Senate, and at least a sliver of insulation for the White House from the whims of individual senators who now hold enormous sway, like the moderates Joe Manchin of West Virginia and Kyrsten Sinema of Arizona.
Mr. Lamb rose to prominence in 2018 when he won a special House election in a district that Mr. Trump had carried by double digits. He won twice more in a redrawn but still politically mixed district, staking out independent positions that included voting against Representative Nancy Pelosi for House Speaker. But while he bills himself as the strongest potential Democratic nominee precisely because of what he calls his Bidenesque, centrist approach, aspects of his record, including on guns and marijuana, are out of step with many primary voters.
“Progressives are the most active in the party, and that makes it tough for Lamb,’’ said Brendan McPhillips, who ran Mr. Biden’s 2020 Pennsylvania campaign and is not working for a Senate candidate.
The early favorite of progressives and presumed front-runner for the Democratic nomination is Lt. Gov. John Fetterman, something of a folk hero to the national left, with some 400,000 Twitter followers who relish his posts in favor of “legal weed” and his frequent swipes at Mr. Manchin and Ms. Sinema for not “voting like Democrats.”
As the 14-year mayor of Braddock, a poor community outside Pittsburgh, Mr. Fetterman tattooed the dates of local homicides on his arm. As lieutenant governor, he has fought to pardon longtime nonviolent inmates.
Known for a casual working wardrobe of untucked tradesmen’s shirts and jeans, or even shorts, and for his imposing presence — he is 6-foot-8 with a shaved head — Mr. Fetterman, 51, hopes to appeal to some working-class white voters who drifted over to support Mr. Trump. He has lapped the field in fund-raising, pulling in $6.5 million this year.
Still, Mr. Fetterman’s challenge is the flip side of Mr. Lamb’s: He could win the May primary but be seen as too liberal for Pennsylvania’s general-election voters. “He’s the candidate I think many Republicans would love to face,’’ said Jessica Taylor, an analyst for the nonpartisan Cook Political Report.
A potential liability in the primary also looms for Mr. Fetterman in a 2013 incident, when he was mayor of Braddock. After hearing what he took to be gunshots, Mr. Fetterman stopped a Black jogger and held him at gunpoint until police arrived. The man turned out to be unarmed and was released. Mr. Fetterman addressed the episode in February, explaining he had made “split-second decisions” when he believed a nearby school might be in danger.
Still, with police and vigilante violence against Black men a highly charged issue for Democratic voters, some party officials and strategists expressed fears that, if nominated, Mr. Fetterman could depress Black turnout. An outside group that supports the election of Black candidates has already run a radio ad in Philadelphia attacking Mr. Fetterman over the incident.
“It’s most certainly an issue,” said Christopher Borick, a political scientist and pollster at Muhlenberg College in Allentown, Pa. “It hasn’t gone away and it keeps resurfacing. It raises red flags.”
In a statement, Mr. Fetterman’s campaign noted that he had been “overwhelmingly re-elected” four months after the incident in Braddock, “a town that is 80 percent Black,” because voters there “know John, and they know this had nothing to do with race.” It added that he had gone on to “run and win statewide, and he is the only candidate running for this Senate seat who has done so.”
If Democratic voters balk at Mr. Fetterman and Mr. Lamb, a path could open for alternative candidates, including Val Arkoosh, a county official in the electorally key Philadelphia suburbs and the only woman in the race, and Malcolm Kenyatta, a telegenic young state lawmaker from North Philadelphia.
Mr. Kenyatta, who would be the state’s first Black and first openly gay Senate nominee if he won, has traveled extensively seeking local endorsements but lags behind his rivals in fund-raising.
Ms. Arkoosh, a physician and the chair of the Board of Commissioners in Montgomery County, the state’s third largest county, has the endorsement of Emily’s List, which backs Democratic women who support abortion rights.
Together, Mr. Fetterman, Mr. Lamb and Ms. Arkoosh significantly out-raised their Republican counterparts in the quarter ending in June.
While Democrats see a model in Mr. Biden’s 81,000-vote victory in the state last year, which swept up suburban swing voters appalled by Mr. Trump, Republicans are currently playing almost exclusively to the Make America Great Again base, retelling the fable of a stolen 2020 election.
There is a proven path to statewide victories for Republicans in Pennsylvania, one taken by two G.O.P. candidates last year who were elected treasurer and auditor general. They did so by running ahead of Mr. Trump in the suburbs of Philadelphia, Harrisburg and Pittsburgh, where many college-educated voters had traditionally supported Republicans but were repelled by the bullying, divisive former president.
Mr. Toomey, the retiring Republican senator, warned recently, “Candidates will have to run on ideas and principles, not on allegiance to a man.’’
But few of the Republicans vying to succeed him seem to have listened.
Sean Parnell, a former Army Ranger who lost a House race last year to Mr. Lamb, sued to throw out all 2.6 million Pennsylvania mail-in votes, a case the U.S. Supreme Court rejected, and has said he supports an Arizona-style audit of Pennsylvania’s 2020 ballots. Donald Trump Jr. has endorsed his Senate bid.
And Jeff Bartos, a real estate developer and major party donor from the Philadelphia area who was expected to appeal to suburban voters, has similarly courted the Trump base, calling for a “full forensic audit” of Pennsylvania’s election, though multiple courts threw out suits claiming fraud or official misconduct.
Neither Mr. Parnell nor Mr. Bartos raised as much money in the recent quarter as a dark-horse candidate, Kathy Barnette, a former financial executive who lost a congressional race on Philadelphia’s Main Line last year. Ms. Barnette has pushed claims of voter fraud on the far-right cable outlets Newsmax and OAN.
A longtime Republican consultant in the state, Christopher Nicholas, said there were three lanes available to G.O.P. candidates: “Super-MAGA-Trumpy, Trump-adjacent, and not-so-much-Trump.”
Lately, he said, almost everyone has elbowed into the “Super-MAGA-Trumpy” lane.
“As a Republican, you have to watch how far to the right you go to win the primary, that it doesn’t do irreparable harm to them in the general election,’’ Mr. Nicholas said.
Mr. Lamb faces a similar challenge as a moderate in the Democratic primary.
He is sure to be hit hard over some past positions, including his opposition to an assault weapons ban in 2019 and his vote the previous year to extend permanently the Trump administration’s individual tax cuts.
More recently, Mr. Lamb has stayed more in step with his party: In April, he endorsed Mr. Biden’s call to ban future assault weapons sales; in May, he endorsed ending the filibuster.
Mr. Lamb said in an interview that the assault on the Capitol had been a turning point for him, particularly in how Republican leaders had come around to embrace Mr. Trump’s false charge that the 2020 vote had been rigged.
He alluded to that again in his announcement speech on Friday: “If they will take such a big lie and place it at the center of the party,” he said of G.O.P. leaders, “you cannot expect them to tell the truth about anything else.”
