Bob Casey and Dave McCormick advance to the general election in Pennsylvania, setting up a key race for Senate control

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.

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.

“Pennsylvania deserves better than Bob Casey,” McCormick said during a victory speech on Tuesday. “At every single time where he could’ve been a leader instead of a follower, he’s chosen to be a follower.”

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.”

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. NBC News projected that both men would win their party’s primaries in Pennsylvania.

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.

Initial vote totals looked like Trump faced a more substantial protest vote than Biden. With roughly 95% of the expected vote counted on Wednesday morning, about 16% of Republican primary voters backed Haley — more than 150,000 in total. Pennsylvania has a closed primary system, so only registered Republicans could vote in that contest, unlike earlier primaries where Democrats and independents had a chance to cast ballots.

But on the Democratic side, with 96% of the expected vote counted on Wednesday, about 5% went to write-ins. Biden, meanwhile, garnered about 88% of the vote while Rep. Dean Phillips, D-Minn., got about 6% support after ending his candidacy last month. Not all counties tabulate write-in votes on election night, so the full scope of any write-in campaign might not be clear until all votes are counted. Still, more than 55,000 write-in votes were cast.

Organizers backing an “uncommitted” vote protesting Biden's handling of the war between Israel and Hamas hoped to garner at least 40,000 write-in votes in their campaign. It’s unclear how many write-in votes were associated with the effort.

The Democratic primary is also only open to registered party members.

In total, more than 163,000 Republican primary voters either voted for Haley or cast write-in votes. On the Democratic side, at least 123,000 voters chose Phillips or submitted a write-in.

Biden eclipsed former President Barack Obama's vote total in the 2012 Democratic primary, the last time an incumbent Democrat ran for reelection. Biden won more than 926,000 votes in this year's primary, compared to about 616,000 for Obama in 2012. That year, about 19,000 Democratic primary voters cast write-in votes.

Biden's raw vote total looks to have exceeded Trump's, who as of Wednesday morning had about 788,000 votes for him counted. In Pennsylvania's 2020 GOP primary, when Trump was an incumbent and did not face a serious primary challenge, he won just north of 1 million votes.

With votes still being counted, Democrats looked to have an edge about about 100,000 voters turn out in their primary compared to the GOP contest. A similar number of votes remain to be counted in each race.

The battle for the House

Further down the ballot, there were a few races of significant intrigue. Chief among them was a House Democratic primary in the Pittsburgh area, where NBC News projects Rep. Summer Lee defeated Edgewood Borough Council member Bhavini Patel.

The race 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 fought off a GOP primary challenge from anti-abortion-rights activist Mark Houck. It wasn't 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.

Fitzpatrick will now face Democrat Ashley Ehasz, an Army veteran whom he defeated by 10 points in 2022, again this fall.

Several general election matchups in competitive House races were also set in Pennsylvania, as Republicans nationally are aiming to hold onto a razor-thin majority in the lower chamber this year.

In the 7th District north of Philadelphia, state Rep. Ryan Mackenzie won the GOP primary, advancing to the what's expected to be a hotly contested general election against Democratic Rep. Susan Wild. Wild won a third term in 2022 by just 2 points after Biden won her district by less than 1 point in 2020.

In the 10th District, which includes Harrisburg, former local TV news anchor Janelle Stelson won a six-way Democratic primary 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.

Stelson had the support of EMILY’s List, a group that backs female candidates who support abortion rights. Trump carried the district by 4 points in 2020.

Elsewhere, Democratic Rep. Matt Cartwright will face Republican businessman Rob Bresnahan in the Scranton-area 8th District, which Trump carried four years ago. And Democratic Rep. Chris Deluzio will take on GOP state Rep. Rob Mercuri in the 17th District in the southwestern part of Pennsylvania, which Biden won by 6 points.

This article was originally published on NBCNews.com