We're starting to see the first results trickle in in Indiana, but you just have to look at another Indiana election to see why you shouldn't overreact when only 1 percent of the vote is reporting ...

—Nathaniel Rakich, 538

Another ex-congressman may make a comeback in southwestern Indiana's 8th District — once one of the most competitive seats in the country but now a reliably Republican seat. The two front-runners in the GOP primary here appear to be state Sen. Mark Messmer and former Rep. John Hostettler. Establishment and tea party Republican groups have invested heavily in this race: America Leads Action has spent $1.6 million to help Messmer and hurt Hostettler, and Protect Freedom PAC is airing ads for Hostettler.

But the main divide in this race seems to be less about governing philosophy and more about foreign policy. For instance, Protect Freedom PAC — which represents former Rep. Ron Paul's libertarian wing of the party — may be with Hostettler because he and Paul were two of only six Republicans who opposed the Iraq war back in 2002. And Hostettler's record on Israel has provoked strong opposition from the American Israel Public Affairs Committee and Republican Jewish Coalition. Citing anti-Israel votes Hostettler took in Congress as well as a book he wrote that blamed the Iraq war on Jewish Americans' efforts to help Israel, these two groups have dropped $2.2 million to attack Hostettler or boost Messmer.

In total, pro-Messmer, anti-Hostettler outside groups have outspent pro-Hostettler, anti-Messmer groups by a whopping $5.1 million to $793,000. (And it's not like Hostettler himself has been able to fight back; Messmer has outraised him $763,000 to $41,000.)

Don't write off two other candidates, either. Surgeon Richard Moss, who has pledged to join the Freedom Caucus, has raised $556,000, while 28-year-old Army reservist Dominick Kavanaugh took in $528,000. That said, given the financial disparity, any candidate other than Messmer has to be considered an underdog.

—Nathaniel Rakich, 538

In the safely Republican 6th District, Rep. Greg Pence — who, like his brother Mike, is conservative but not angry about it — is stepping aside, and it's very much an open question whether he'll be replaced by a moderate or a hardliner.

Former Indianapolis City-County Councilor Jefferson Shreve, the owner of a successful storage company, is the top fundraiser in the GOP primary thanks to a $4.5 million loan to his own campaign — more than his six opponents have raised combined. But wealthy state Rep. Mike Speedy has also loaned himself $1.3 million and he's using it to remind voters of the moderate positions, like supporting gun control, that Shreve took last year during his failed bid for mayor of Indianapolis (a significantly bluer constituency than the 6th District). To underscore the ideological fault lines of the primary: Shreve has the endorsement of the U.S. Chamber of Commerce, while Speedy is backed by the tea party group Americans for Prosperity and Susan B. Anthony Pro-Life America.

No other active candidate in the race has raised more than $200,000 except businessman Jamison Carrier, who raised the most from actual donors ($115,000) in addition to a $750,000 self-loan. There's a chance that Carrier sneaks up the middle between the two front-runners, as he's the only one of the three from a part of the district that's not Indianapolis, which accounted for just 23 percent of the Trump vote in the district in 2020, according to Daily Kos Elections. There's no polling here, though, so it's hard to know whether Carrier's geographic advantage will erase Shreve's and Speedy's financial edge.

—Nathaniel Rakich, 538

Just one House member has lost their primary so far this year — Rep. Jerry Carl in Alabama's 1st District — but Spartz could join that unfortunate group tonight. As Geoffrey mentioned, Spartz dug herself into a bit of a hole by announcing last year she would not seek reelection; she only recently changed her mind and didn't begin advertising on TV until early April.

Spartz isn't the only member in primary trouble; a number of Republicans and Democrats alike are facing challenges from their right. In Texas on May 28, moderate Rep. Tony Gonzales faces a runoff against YouTuber Brandon Herrera that has attracted millions of dollars in advertising and has gotten very personal in recent weeks. In West Virginia, Rep. Carol Miller has begun airing negative ads against her opponent, former state Rep. Derrick Evans, ahead of her May 14 primary. And two South Carolina Republicans are facing competitive primaries on June 11. In the 1st District, Rep. Nancy Mace faces former state health department director Catherine Templeton in a primary that has seen the anti-tax Club for Growth and other super PACs invest millions; in the 4th District, Rep. Will Timmons and his allies are taking seriously a challenge from state Rep. Adam Morgan.

But wait, there's more: Florida Rep. Daniel Webster nearly lost his primary last cycle after being caught flat-footed and will have to get past former state Rep. Anthony Sabatini for his 11th District seat on Aug. 20. And Washington's 4th District Rep. Dan Newhouse might have a serious fight on his hands in his Aug. 6 primary, which also includes Trump-backed former NASCAR driver Jerrod Sessler and 2022 Senate nominee Tiffany Smiley. Newhouse only won 25 percent of the vote in the 2022 all-party primary for this seat, so he's clearly vulnerable. But no Democrats have filed to run yet, and Newhouse — who voted to impeach Trump in 2021 — stands a better shot of winning the bulk of those Democratic votes than Sessler or Smiley.

On the Democratic side, the two members most likely to encounter serious primary trouble are both members of the progressive "Squad." In New York's 16th District, Rep. Jamaal Bowman is fending off a well-funded challenge from Westchester County Executive George Latimer; the June 25 primary will be among the most expensive this election cycle if the AIPAC-affiliated United Democracy Project gets involved. And Missouri's 1st District Rep. Cori Bush was trailing by double digits against St. Louis County prosecutor Wesley Bell in the only public survey of her Aug. 6 primary.

—Jacob Rubashkin, Inside Elections