Pennsylvania and national Republicans are breathing easy after state Sen. Doug Mastriano (R) surprised many by announcing that he will forego a run for Sen. Bob Casey’s (D-Pa.) seat and support whomever the eventual nominee is.

Mastriano made the announcement after days of speculation that he would jump into the primary race and make life difficult for national Republicans. Last November, he lost to Gov. Josh Shapiro (D) by nearly 15 points in the gubernatorial race, which the GOP establishment viewed as proof that the hard-right lawmaker is not viable in a statewide general election. 

One Pennsylvania-based GOP operative told The Hill that politicos in the state “universally” were “pretty shocked” by the decision. 

But it will be considered good news for Republican leadership in the Senate. Many, including Senate Minority Leader Mitch McConnell (R-Ky.), blamed Trump-backed candidates who questioned or denied the results of the 2020 election for the party’s losses in the midterms. And Mastriano was a leading voice advocating for overturning Trump’s loss.

The anonymous Pennsylvania operative said Mastriano remaining on the sidelines was the best outcome for potential candidate-in-waiting David McCormick, who could be looking at a mostly clear path through the primary and into a general election against Casey, the three-term senator with one of the most famous political names in the commonwealth’s history. 

“It means everything,” the operative said about the importance of Thursday’s announcement for McCormick. “Mastriano served it up on a silver platter by saying, ‘I don’t care who the candidate is.'”

All eyes now shift to McCormick, who lost the Senate GOP primary narrowly to Mehmet Oz last year, as he continues to mull over a potential run for the seat.

McCormick for months has been doing everything a prospective candidate would be doing — meeting with county chairs and influential Pennsylvania GOP leaders, and keeping his name in the news with a book and an ongoing book tour. While Mastriano announced his plans Thursday night, McCormick was headlining a book event in Harrisburg, a Pennsylvania Republican source told The Hill. 

The ex-Bridgewater Associates CEO has said that he remains undecided about a bid but he remains the focus of national Republicans. Sen. Steve Daines (R-Mont.), the chairman of the National Republican Senatorial Committee, has already indicated that he is prepared to back him, as has the Senate Leadership Fund, which is run by allies of McConnell.

However, multiple Pennsylvania GOP sources indicated that if McCormick does officially enter the fray, he does not plan on self-funding his campaign with anywhere close to the $14 million he spent on the primary last year against Oz. 

“He’s not going to spend what he spent last time,” a second Pennsylvania-based GOP operative told The Hill, adding that he believes McCormick will have to raise $100 million in total to be competitive against Casey. 

Rob Gleason, a former chairman of the Republican Party of Pennsylvania, added that McCormick has met with a number of donors as part of his legwork for a second bid. Gleason supported McCormick last year and plans to do so again, arguing that McCormick is putting himself in a much better position this time around than he was last year. 

“He’s experienced now. … He’s spent a whole cycle running, developing relationships. He’s really understanding how to be successful statewide,” Gleason told The Hill, noting that unlike last cycle, he will not be running against a fellow multimillionaire. “Being educated about being a candidate makes you much stronger this time around.”

If he runs, McCormick is expected to make an announcement in late summer or early fall, a source close to him said.

Until then, strategists believe McCormick’s main job has to be coalescing Republican voters behind him, even if he does end up receiving a primary challenge. Included in that group are supporters of Mastriano, whose turnout could make-or-break his chances in a general election Casey. 

The first Pennsylvania-based GOP operative said it was smart of McCormick to thank Mastriano specifically in the beginning of his statement reacting to the state senator’s announcement. 

“He needs to at least hold hands … with Mastriano to bring his supporters along with him to the general. They need to come out for McCormick,” the operative said. “There is no second option. There is no Plan B. There are no other candidates that can match up with Casey.”

The operative added that Mastriano’s decision will pay financial dividends for McCormick and speculated that he could be saving upwards of $15-20 million that could be used ahead of next November. 

Every resource will be needed to take down Casey, the three-term senator who is widely viewed among Pennsylvania Republicans as a vanilla candidate and an extremely inoffensive and unproductive senator. However, many are clear-eyed about how difficult it will be to defeat him in a presidential year; he has handily fended off two reelection challenges, including in 2012 when he outperformed then-President Obama. 

“It’s absolutely going to be a very, very difficult job to beat Casey with anybody, because he’s more popular than people think,” the second Pennsylvania-based GOP operative said. “There’s not many people that don’t like Bob Casey. There’s no reason to hate Casey.”