Democratic Sen. Bob Casey and Republican Dave McCormick are officially set to face off in Pennsylvania’s high-stakes Senate battle this fall after winning their uncontested primaries on Tuesday, NBC News projects.

Casey, a three-term incumbent, and McCormick, who rallied the Pennsylvania GOP establishment behind his candidacy after announcing his bid last year, will now sprint toward the November election in one of the most bitterly contested, expensive Senate races in the country. The race is among a handful that could tip the balance of power in Congress’ upper chamber.

For McCormick, a hedge fund executive and former official in President George W. Bush’s Treasury Department, his 2024 run comes on the heels of a failed 2022 bid against celebrity doctor Mehmet Oz, who narrowly defeated him in a Republican primary with former President Donald Trump’s backing. Oz went on to lose to Democrat John Fetterman in the general election.

This time around, McCormick has the support of Trump, as well as GOP leaders across Pennsylvania. 

“It’s a big day in Pennsylvania and we hope the people get out there and vote,” Trump said outside his criminal hush money trial in New York on Tuesday. “It’s important to vote to let them know that we’re coming on November 5th. We’re coming big. Today’s preliminary but still it’s very important and maybe they’ll think also about the very good person who’s running for the Senate in Pennsylvania, Dave McCormick.”

But even with a unified GOP behind him, McCormick faces an uphill battle. Republicans have lost race after race in the Keystone State following Trump’s shocking upset victory there in 2016. And Casey, the son of the state’s former governor, often polls ahead of President Joe Biden in the state.

“Oh, the guy from Connecticut?” Fetterman told NBC News of McCormick, who Democrats have lambasted for maintaining a Connecticut residence. “He loves Connecticut and he loves working and investing in Chinese companies. And I don’t think that’s a winner in Pennsylvania, but I guess we’re going to find out. Bob Casey is going to smoke him.”

Possible presidential primary protest votes 

The top of the ticket in Pennsylvania on Tuesday lacked drama, as not only were both Casey and McCormick running unopposed, but the presidential primary amounted to a formality as well, with both Trump and Biden having already clinched their party’s nominations.

But there was intrigue beneath the surface, as voters on both sides had the chance to submit protest votes on Tuesday. There was an organized effort to get Democratic voters to write in “uncommitted” on their presidential primary ballots to express opposition to Biden’s handling of the Israel-Hamas war. And Nikki Haley, who dropped out of the race in early March, still appeared on the Republican ballot. 

And with presidential and Senate primaries amounting to formalities, turnout could offer some clues as to which side has more enthusiastic supporters in the critical battleground state ahead of the November contest.

“If folks are excited and they’re going out to vote in a non competitive primary, I do think it kind of tells a lot,” Nick Gavio, a progressive strategist working with the Working Families Party, said.

About 1.1 million Pennsylvanians voted in the 2020 presidential primary, one in which Trump was the incumbent and not facing a serious challenge. About 1.6 million voters in the state turned out that year to cast ballots in the Democratic primary, which Biden had already secured by then. Biden won the state in November by about 80,000 votes.

The battle for the House 

Further down the ballot, there are a few races of significant intrigue. Chief among them is a House Democratic primary taking place in the Pittsburgh area pitting Rep. Summer Lee against Edgewood Borough Council member Bhavini Patel.

The race has tested the power of sentiment over the war in Gaza, as Lee is the first among the progressive lawmakers who have been staunch critics of the Israeli war effort to face down a primary. And part of her district includes a prominent historically Jewish neighborhood, Squirrel Hill, that was home to the worst antisemitic attack in U.S. history in 2018.

But Lee, a member of the “Squad” along with fellow progressives such as Alexandria Ocasio-Cortez in the House, was widely seen as a favorite ahead of Tuesday’s contest, as pro-Israel groups that spent against her in her initial 2022 primary opted against doing so this time. 

Lee’s opponent, Bhavini Patel, was boosted by an outside expenditure from GOP megadonor Jeffrey Yass. Patel denounced Yass, but Lee and allies portrayed her as a conservative Democrat because of Yass’ involvement. Pennsylvania’s 12th District is solidly Democratic. 

In eastern Pennsylvania, another House primary shaped up as one of the more important battles of the night as Rep. Brian Fitzpatrick, R-Pa., looked to fight off a primary challenge from anti-abortion-rights activist Mark Houck. It’s not the first time Fitzpatrick, a moderate Republican and former FBI agent, has faced a challenge from the right in the 1st District, which Biden carried in 2020.

In the 10th District, which includes Harrisburg, six Democrats are vying to take on GOP Rep. Scott Perry, the former chairman of the hard-right House Freedom Caucus who was involved in Trump’s efforts to overturn the 2020 election results. Trump narrowly carried the district in 2020. 

General election matchups for competitive races in Pennsylvania’s 7th, 8th, and 17th districts will also be set. Republicans are aiming to hold onto a razor-thin majority in the lower chamber this year. 

Other down ballot races included a five-way Democratic primary and two-way Republican battle for attorney general and one-on-one Democratic contests in primaries for treasurer and state auditor as Democrats look to unseat Republican incumbents this fall.