Conor Lamb has two big problems.

To win Pennsylvania’s Democratic Senate nomination, he has to catch John Fetterman. And he has to do it with less money. Allies of the Pittsburgh-area congressman are hoping a new super PAC can help overcome both, by raising cash from big donors to close a $3 million gap with Fetterman, the Democratic front-runner.

But it’s not clear if that cavalry will arrive — especially without support from national Democrats like Senate Majority Leader Chuck Schumer (D., N.Y.) or the allied groups that factored so heavily into Pennsylvania’s 2016 Senate primary.

That leaves Lamb with even more to do to accomplish an expensive two-pronged task: raising his own profile statewide, while pulling down Fetterman. The lieutenant governor has double-digit leads in early polling, and more than twice as much cash for the primary.

The scope of Lamb’s challenge became clearer Monday when Fetterman announced a TV ad buy, the first significant one of the Democratic contest. Fetterman had $5.3 million in his campaign fund to start the year. Lamb had $3 million — but only $2.3 million available for the primary.

So while Democrats watching the race say the contest has still hardly begun, they also say key factors favor Fetterman.

“All of the polling makes me think Fetterman’s lead is real, but that doesn’t mean it’s firm,” emailed J.J. Balaban, a Democratic strategist from Philadelphia who has worked on Senate races. “But it will take money to displace him and I’m more skeptical now ... that Lamb has the resources to lift himself up and pull Fetterman down.”

If Lamb gets major support from outside groups, “there is plenty of time for him to prevail,” Balaban added. “But that’s a big if.”

» READ MORE: The Pennsylvania Senate money race in 8 charts

Money and TV aren’t the only factors in elections, but they’re important elements in a state as large as Pennsylvania, where reaching a critical mass of voters requires mass communication. Pennsylvania’s Senate race is on track to be one of the most pivotal and expensive in the country, one that could help decide control of the chamber.

Ultra-wealthy Republican candidates are already flooding TV, potentially raising advertising rates.

A third major Democrat in the race, State Rep. Malcolm Kenyatta, has impressed many with his endorsements and working-class message, but has an even tougher hill to climb. His $285,000 in campaign cash has many writing off his chances in such a pricey race.

Lamb is pitching himself as the strongest candidate to win the high-stakes election, especially in a year that looks daunting for Democrats. But his struggle to close ground with Fetterman so far has been noticed in Pennsylvania and Washington. That’s made for a vastly different dynamic from 2016, the last time Pennsylvania Democrats had a major Senate nomination fight.

National Democrats saw that year’s unorthodox front-runner, Joe Sestak, as unacceptable and put a gorilla-sized thumb on the scale. Millions of dollars from national groups poured in to help Katie McGinty overcome Sestak’s early lead. The party had also weighed in heavily in 2010, when Sestak defeated Republican-turned-Democratic Sen. Arlen Specter.

This time, there are questions about Fetterman’s durability, his ability to handle intense scrutiny, and potential weaknesses. But national Democrats see enough upside that they’re not trying to stop him. Nor have party officials in Washington been overwhelmed enough by Lamb to elevate him, even though he seemingly fits the national party profile, having won tough House races in competitive districts.

Fetterman also doesn’t have the openly antagonistic relationship with national Democrats that Sestak did.

“We’re keeping open lines of communications with all of the candidates,” said Patrick Burgwinkle, a spokesperson for Senate Democrats’ campaign arm. “We haven’t issued endorsements in any challenger races — yet — but we are not taking anything off the table.”

Lamb’s campaign downplayed questions about national support, pointing instead to his busy campaign schedule and a string of major endorsements in Pennsylvania, including the Philadelphia laborers’ and building trades unions, and the Pittsburgh arm of the state’s teachers’ union.

“Pennsylvania Democrats aren’t looking to a building in D.C. to find out what Conor is talking about every day: how he’s beaten Trump’s people three times in three Republican districts and will do it again,” said Lamb’s campaign manager Abby Nassif-Murphy. “We’re running a grassroots campaign, building a winning coalition and gaining support and momentum where it really counts — on the ground, from dozens of labor unions, elected officials and Democratic activists all over the state.”

“We will have the money and the support we need to make sure Pennsylvania Democrats know that Conor Lamb is the candidate who can win this seat in November,” she added.

» READ MORE: Conor Lamb and John Fetterman are running like Joe Biden and Bernie Sanders

A super PAC could help Lamb close the gap. But political operatives and fund-raisers warn that raising money for a super PAC (often called an “independent expenditure” or IE group) can be a lot harder than it sounds — especially in a primary, when voters are picking between different flavors of Democrat.

“An IE that isn’t explicitly backed by Schumer is unlikely to be of the size Lamb needs,” said Balaban.

While big-spending super PACs are common, it’s hard to get national donors to pony up five- and six-figure checks for individual candidates in primaries, said Aubrey Montgomery, a longtime Democratic fund-raiser from Philadelphia. A New York banker or Silicon Valley executive is less likely to know the nuances separating Pennsylvania’s primary candidates, or have a strong allegiances to one of them.

“They ultimately care about flipping the Senate seat, but it’s not clear that they want to get involved in picking the nominee,” Montgomery said.

Even some top local Democratic fund-raisers with longtime party ties, including Philadelphia attorneys Alan Kessler and Ken Jarin, said they’re not getting involved with the Lamb super PAC. Jarin said hghe’s still “enthusiastically” supporting Lamb’s campaign.

Super PACs can accept donations above and beyond the normal $5,800 federal limits. But they aren’t allowed to coordinate with candidates, and they don’t get the lower TV rates candidates do, so their money doesn’t go as far.

The Lamb group, Penn Progress, has touted an $8 million spending target, though many Democrats doubt its ability to reach that. It does have some major names supporting it, including the celebrity political strategist James Carville and Mary Pat Bonner, a prolific Democratic fund-raiser with Pennsylvania ties.

“We’re just getting started,” said Eric Smith, the PAC’s executive director. “It’s too early to make any early judgements.”

Lamb supporters predict big donors will come because of the stakes of the race and, they argue, because only he has the moderate profile that fits Pennsylvania.

“People realize he’s the only one that can win the race for the Democrats,” said Allegheny County Executive Rich Fitzgerald.

“Far-left forces have not served us well,” added Steve Cozen, an attorney and major Philadelphia Democratic donor who wrote a $10,000 check to the super PAC, one of its first donations. “We need a moderate, centrist candidate if we’re going to replace Pat Toomey with a Democrat, and Conor’s the guy.”

(Toomey, the incumbent Republican, isn’t seeking reelection.)

Balaban and other Democrats say Lamb still has a path to victory.

But he’ll need more money.

Staff writer Julia Terruso contributed to this article.