On the surface, the races for governor and U.S. Senate in Pennsylvania look like a big national draw.

President Trump held a rally in Wilkes-Barre last month for Rep. Lou Barletta, the Republican Senate candidate. Vice President Pence held fund-raisers here over the summer.

On Friday, Trump's eldest son, Donald Trump Jr., attended the state GOP's fall dinner, and former President Barack Obama campaigned in Philadelphia on behalf of Sen. Bob Casey and Gov. Wolf, both Democrats.

And yet: National Republican groups that spend tens of millions of dollars in key races appear to be writing off the top of the ticket in the Keystone State, where polls show double-digit leads for the Democratic incumbents and Trump's approval ratings under 40 percent.

As of this week, groups such as the Republican Governors Association, the Senate GOP's campaign committee, and the super PAC aligned with Senate Republicans had not spent a dime on television ads in Pennsylvania or reserved airtime here, according to a review of federal filings and interviews with media buyers who track the races.

That's in contrast with Republican outside groups' heavy spending in Pennsylvania House races that will help determine which party controls Congress after the November midterm elections. For example, the National Republican Congressional Committee and the Congressional Leadership Fund, a super PAC aligned with Speaker Paul Ryan, have spent more than $1 million trying to boost Republican Rep. Brian Fitzpatrick over Democrat Scott Wallace in the Bucks County-based First District.

"If they feel they have a shot at victory, they will invest. If there's not a path to victory," they won't, said Rob Jesmer, former executive director of the National Republican Senatorial Committee (NRSC).

"It's usually incumbent on the in-state campaign to make that case," he said.

The NRSC and Senate Leadership Fund political action committee have spent a combined $34 million on independent expenditures and electioneering in eight states this year, according to data compiled by the Center for Responsive Politics.

The top Democratic outside groups aren't spending on the top of the ticket, either, betting that the candidates don't need their help.

Scott Wagner, the Republican nominee for governor, in January. The Republican Governors Association has not spent money on TV ads in Wagner’s race against Democratic Gov. Wolf.
Bradley C Bower/ For the Inquirer
Scott Wagner, the Republican nominee for governor, in January. The Republican Governors Association has not spent money on TV ads in Wagner’s race against Democratic Gov. Wolf.

After racking up big wins in governors races during the Obama administration, the GOP is defending 26 incumbents and Republican-held offices that are now open. They're also competing in such Democratic states as Connecticut, where outgoing Gov. Dan Malloy's poor approval ratings have created an opening for Republicans.

There are tough fights in such traditional swing states as Ohio and Florida, and Republicans are also trying to rescue Gov. Scott Walker, who is seeking a third term in Wisconsin. Even deep-red Kansas is a battleground with the ascendance of Trump ally Kris Kobach, a controversial figure who made his name on unsubstantiated claims of voter fraud.

In addition to being squeezed by the national political terrain, GOP nominee Scott Wagner has struggled to raise cash from traditional Republican power brokers in Pennsylvania who have chafed at his Trump-like approach.

One outside group backing Wagner is Americans for Prosperity, the free-market group financed by the billionaire Koch brothers.

In a video posted on Facebook two weeks ago, Wagner said he needed to raise at least $7 million over the next month "to be able to battle Tom Wolf and his socialist allies: Tom Steyer, George Soros, the public-sector unions."

"The money," he said, "is pouring into Tom Wolf's bank account a million dollars at a time."

Wolf is the only Democratic governor running for reelection in a state Trump won in 2016.

A Wagner campaign spokesperson said Wagner would "continue to make grassroots fund-raising appeals throughout the remainder of the campaign in order to raise as much money as possible."

RGA spokesperson Jon Thompson said, "If we see an opportunity to make an impact or to get involved in a way that could move the needle, we will."

"This is when you're starting to consolidate on top states you can win, because some of them are looking really dangerous," said Colm O'Comartun, former executive director of the Democratic Governors Association. "This is not a time where you start to invest in a state that looks like it's long gone in order to try to make it viable."

Gov. Tom Wolf in May.
TIM TAI / Staff Photographer
Gov. Tom Wolf in May.

In Washington, Republicans are clinging to a slim 51-49 majority in the Senate. The map is considered favorable to the GOP, as the party tries to knock out Democrats in states that Trump won in 2016, and where the president remains popular, such as  West Virginia and North Dakota. They're playing defense in swing states such as  Nevada but also in more conservative ones such as Arizona and Tennessee, where Republican retirements have left open seats.

Trump is even heading to deep-red Texas, where Republicans have declared a political emergency to stave off Democratic Rep. Beto O'Rourke's challenge to Sen. Ted Cruz.

So Barletta, an immigration hard-liner and early supporter of Trump's, is largely on his own against Casey, a two-term incumbent with high name recognition and a $10 million war chest. Barletta had $1.5 million in his campaign account as of June 30.

The Barletta campaign said that the White House was committed to the congressman and that as the race "continues to tighten, we fully anticipate further investment in Pennsylvania."

One political headwind facing Pennsylvania Republicans: Polling by Franklin and  Marshall and NBC News/Marist shows that fewer than 40 percent of registered voters in the Keystone State approve of Trump's job performance. Fifty-three percent disapprove, according to the NBC August survey.

Obama's ratings were similar at this point in 2010, when Republicans won the governor's office and a U.S. Senate seat. Another advantage for incumbents such as  Wolf and Casey: Voters are more optimistic about the direction of the state now than they were in 2010 or 2014, and Democrats also have an edge in voter enthusiasm, according to Franklin and Marshall.

A plurality of voters approve of the two incumbents.

Sen. Bob Casey with California Sen. Kamala Harris at a campaign event in July.
HEATHER KHALIFA / Staff Photographer
Sen. Bob Casey with California Sen. Kamala Harris at a campaign event in July.

Democratic resistance to the president has helped fuel the party's strong performance in special elections, including in Pennsylvania, since Trump took office.

John Brabender, a Republican consultant and admaker advising the Barletta campaign, said national Republican groups typically hit the airwaves closer to Election Day in Pennsylvania, because it's a big state with expensive media markets.

"They know if they go up in late August/early September, they're not going to be able to run very much," Brabender said. "They'd much rather come in at the end of the race when voters are paying the highest level of attention."

He added that Trump's rally in Wilkes-Barre, which attracted plenty of media exposure, was worth about $1 million in advertising.

Strategists in both parties agree that Pennsylvania is expensive, but they privately doubt that outside groups will spend much, if any, on the race unless the polls tighten.

"I don't see anything that would say the Senate race is competitive," said Jesmer, the former executive director of the Senate Republicans' campaign arm.

Even so, Trump and his surrogates continue to show up.

"As far as 2020 goes, they can't afford to lose a handful of House races and expect to still be competitive in that state, when he's on the ballot again," said Jennifer Duffy, an analyst at the nonpartisan Cook Political Report.