Reporting live from the 12th District, there have definitely been some shenanigans playing out here in the Lee-Patel race, Geoffrey, so I'll be interested to see what happens with the other Squad challenges. For example, the 14th Ward Independent Democratic Club, an influential progressive group located on the East End in Pittsburgh, endorsed Patel over Lee. In 2022, the IDC endorsed Lee over the more moderate Steve Irwin, so it may look like the club has had a change of heart.

However, there's much more happening behind the scenes. Allegheny County's 14th Ward includes Squirrel Hill, traditionally the home of Pittsburgh's orthodox Jewish community. In January of this year, over 150 new members became a part of the IDC in advance of their annual votes on board members and endorsements, growing the club's membership by more than 50 percent. The new IDC members ousted board members that they considered too pro-Palestine, and were instrumental in directing the group's endorsements. So while it may appear to voters that a progressive group is abandoning Lee, a peek behind the curtain reveals quite a bit more is going on.

—Mary Radcliffe, 538

In the Pittsburgh-based 12th District, progressive Rep. Summer Lee could be vulnerable against Edgewood Borough Council member Bhavini Patel in the Democratic primary. Two years ago, in her first bid for this seat, Lee only won her primary by less than a point. And Patel's challenge has turned into a referendum on Lee's party bona fides. Behind this is Lee's membership in The Squad, a group of progressive House Democrats who've often been at odds with party leaders. This has been especially apparent in the intraparty debate over the Israel-Hamas conflict in Gaza, most recently demonstrated by The Squad joining with about one-sixth of House Democrats in voting against foreign aid to Israel.

Lee's critics have often portrayed her as more dogmatic than pragmatic, a theme Patel's campaign has played up by arguing that Lee wants to undermine Biden and the Democratic Party. She has run ads attacking Lee for opposing the Biden administration and criticized Lee's support for the "uncommitted" movement in the presidential primary that wants Biden to adopt a less pro-Israel stance. Lee has countered by emphasizing her ability to bring federal investment to the district and her pro-choice record. Her campaign has also criticized "Republican-funded super PACs" for meddling — a reference to Patel's backing from Moderate PAC, a group mostly funded by a GOP donor, and the potential influence of the bipartisan American Israel Public Affairs Committee, which has said it might spend $100 million against progressives this cycle.

Heading into the primary, Lee probably has the upper hand. We have no polls, but Lee had outraised Patel nearly 4-to-1 ($2.3 million to $602,000) as of April 3. Meanwhile, outside spending has run about even, according to OpenSecrets. Surprisingly, though, AIPAC's super PAC has not spent money against Lee despite investing $3.9 million to stop her in the 2022 primary. That may mean that AIPAC thinks Patel can't win, that she already has sufficient support and/or that support associated with AIPAC could harm Patel more than help her.

—Geoffrey Skelley, 538

It'll still be a little while before full results start rolling in from Pennsylvania, and, in the meantime, allow me to suggest some easy listening. Yup, it's the 538 Politics podcast!

On Monday's episode we previewed a couple of tonight's races in Pennsylvania and talked about the state's significance come November. We also considered whether House Speaker Mike Johnson can last as something of a coalitional speaker, frequently relying on votes from Democrats to get legislation passed. And lastly, we tested our knowledge of what Americans think about climate change, according to the polls. Give it a listen!

—Galen Druke, 538

Happy primary day to those who celebrate! (That's us, fellow Pennsyvlanians.)

The Keystone State is already in the public eye this election cycle, as it's expected to be a battleground state for both the presidential race and a critical U.S. Senate race between incumbent Democratic Sen. Bob Casey and Republican David McCormick. And there are consequential races down the ballot, too: Several competitive U.S. House races could impact the balance of the House majority, while Democrats are hoping to compete for control of both chambers of the state legislature to earn their first state government trifecta in more than 30 years.

And while the candidates for president and Senate are set, today's primary contests will determine just who's on the ballot from each party in those key down ballot races. Tonight, we're closely tracking a handful of significant U.S. House races, including progressive Rep. Summer Lee's bid to hold off a more moderate challenger; moderate Republican Rep. Brian Fitzpatrick's challenge from the hard right; and a three-way GOP primary to decide who will face off against Rep. Susan Wild in one of the most competitive House races this fall. We've also got our eyes on some hotly contested primary contests for statewide offices like attorney general and a number of spicy state legislative races.

As usual, we'll be here to guide you through it all with the latest results and analysis throughout the evening. We should start seeing results come in shortly after polls close at 8 p.m. Eastern. Thanks for joining us!

—Tia Yang, 538

In Bucks County, just outside Philadelphia, steadfast moderate Republican Rep. Brian Fitzpatrick is facing a primary challenge from the right for his seat in the 1st District. Mark Houck is an anti-abortion activist and head of a nonprofit ministry group for Catholic men who made a name for himself as a bit of an anti-abortion martyr when he was charged with assault (but found not guilty) after shoving a 72-year-old clinic volunteer in 2021 while protesting outside a Planned Parenthood in Philadelphia. Fitzpatrick was first elected to Congress in 2016, succeeding his brother (the late former Rep. Mike Fitzpatrick). He's faced a primary challenger in every election since, but has always triumphed.

Fitzpatrick has made a reputation for himself locally and on the Hill as a moderate who keeps his distance from the MAGA right. He's got a track record of bipartisanship and moderate policy stances in Congress and refused to endorse Doug Mastriano, the GOP's far-right nominee for governor in 2022. He even snubbed Trump's visit to Bucks County earlier this month. His position on abortion has been a bit less clear — there's no mention of abortion on his reelection campaign website — though he has drawn ire from abortion rights groups. He's certainly no culture warrior like Houck, whose organization opposes "same-sex attraction disorders" and pornography, and works to shut down "sexually oriented businesses."

But whoever wins this primary isn't necessarily a shoe-in for the seat. Fitzpatrick or Houck will be going up against Democrat Ashley Ehasz. Fitzpatrick defeated Ehasz in 2022 by 10 percentage points, but the area is purple and shows signs of shifting blue — Biden won the district in 2020, and Democrats swept all five seats up for grabs in a recent local school board election. Fitzpatrick is the lone Republican in the districts surrounding Philadelphia, though his is the whitest of those collar counties and the conservative areas of the county are increasingly polarized. That could mean Fitzpatrick faces serious competition from Houck in the party primary, but Houck's far-right leanings could tilt the general election contest toward Democrats if he makes the ballot in November.

—Kaleigh Rogers, 538