4 primaries to watch in New Jersey, Montana and Iowa

While 538 won't be live-blogging the results this time around (though we're always live-blogging in our hearts), that doesn't mean Tuesday's primaries won't have any action. Between a criminal trial casting a shadow on multiple races in the Garden State, a hotly contested swing seat in Iowa, and a million-dollar race for an open seat in Montana, there's plenty to keep an eye on as voters head to the polls this week. Here are four races to watch in New Jersey, Iowa and Montana:

New Jersey

Races to watch: 3rd and 8th congressional districts
Polls close: 8 p.m. Eastern

Though overshadowed by another politician's criminal trial these past few weeks, New Jersey Sen. Bob Menendez's corruption trial has also been unfolding in Manhattan. In many ways, that case serves as the backdrop to the most compelling primary races in the Garden State on Tuesday. For a minute, it looked like the Democratic primary race for Senate to replace Menendez would be the hot one to watch. (Menendez announced in March he would not seek reelection as a Democrat under mounting pressure and multiple federal charges, though he appears likely to run as an independent.) But when New Jersey First Lady Tammy Murphy withdrew from the race, she effectively left the nomination in the lap of her top competition, Rep. Andy Kim.

In a game of political musical chairs, that left Kim's seat in New Jersey's 3rd District, in the middle of the state, open. But the Senate primary also created other ripple effects across New Jersey politics. Namely, while Murphy was still in the race, Kim and other Democratic primary candidates launched a lawsuit to eliminate the Garden State's controversial use of "county line" ballots. These ballots list candidates that receive the support of local party officials in a prominent, separate line on the ballot. A federal judge ultimately barred these ballots from being used in all of this year's Democratic primaries (the GOP still has it, for now at least), leading other races — including in the 3rd — to suddenly become more competitive.

Five Democrats are vying for Kim's seat, including state Assembly member and deputy speaker (and doctor and lawyer) Herb Conaway. Conaway won the endorsement of all three county Democratic conventions in the district and, had "the line" not been abolished, would have been the clear favorite. But without the added boost of the line ballot, Conaway has some competition, in particular fellow Assembly member Carol Murphy, the Democratic whip who represents the state's 7th Legislative District alongside Conaway. However, Conaway still has a fundraising advantage, having raised over half a million dollars while the next highest raiser (Murphy) drew in over $160,000.

The most recent polling, from April, showed Conaway with a 14-point lead over Murphy. And even Murphy's campaign polling showed her behind Conaway, though a majority of respondents in both polls were still undecided. Still, it's worth watching to see just how long the shadow of the county line ballot may be. Looking forward to the general election, this district used to be somewhat competitive, but got a lot bluer in the most recent redistricting cycle. Under the current map, the 3rd District went for President Joe Biden by 14 percentage points in 2020, so it's a decent bet that whoever wins the Democratic primary will sail into the seat.

Meanwhile, up in the 8th District — which includes some of the most urban stretches of the state including Jersey City, Hoboken and Elizabeth — Rep. Rob Menendez is seeking reelection to a second term. And yes, there is a relation: Menendez is the Senator's son. He's facing two challengers in the Democratic primary, though his main competition is civil rights attorney and Hoboken Mayor Ravi Bhalla. Bhalla has been leveraging the legal troubles of his competitor's father to his advantage. In his campaign announcement video, Bhalla said he believes "America is better than [...] the politicians who strive only to serve themselves," over a clip of Menendez walking alongside his father. And he's been all too happy to bring up the elder Menendez's legal troubles when trading barbs with the son online.

But Rep. Menendez hasn't shied away from the subject, releasing an ad where he accused Bhalla of running "against my father because he's scared of running against me." Though Bhalla has outraised Menendez, the incumbent Congressman has benefited from outside spending, and polling has shown the two fairly evenly matched. It will definitely be a race to watch, as we see whether the son can outrun the sins of the father, or if Democrats in this solid blue district want a fresh start.

Iowa

Race to watch: 3rd Congressional District
Polls close: 9 p.m. Eastern

With such a closely-divided U.S. House of Representatives, the outcome in hotly contested seats like Iowa's 3rd District will likely decide control of the chamber this November. In 2022, Republican Rep. Zach Nunn flipped this Des Moines-based seat for the GOP with a margin of victory smaller than 1 percentage point, and former President Donald Trump would've carried the district by just 0.3 points in the 2020 presidential election. Two Democrats are vying in Tuesday's primary for the right to take on Nunn: former U.S. Department of Agriculture official Lanon Baccam and nonprofit leader Melissa Vine.

Baccam, whose parents immigrated to Iowa from Laos in 1980, is the clear favorite in the Democratic primary. Much of the party establishment has rallied behind him, including the Democratic Congressional Campaign Committee, which backed Baccam's candidacy well before the primary. Baccam has thoroughly outraised Vine, too, having brought in nearly $2 million to her $155,000 as of mid-May. And Vine made news for the wrong reasons in May when the state Ethics and Campaign Disclosure fined Vine and her former campaign manager for making contributions to a state political action committee in other people's names ahead of an endorsement vote by the group. Still, Vine can't be written off: She has centered her campaign around protecting abortion rights and her nonprofit work to help women struggling with trauma and mental health issues.

Montana

Race to watch: 2nd Congressional District
Polls close: 10 p.m. Eastern

The eastern two-thirds of Montana make up the state's dark-red 2nd District, which sits open following the retirement of Republican Rep. Matt Rosendale. The incumbent certainly kept the political world guessing this election cycle, as he announced a long-expected bid for the U.S. Senate in early February, only to quickly drop out after Trump endorsed another Republican contender, businessman Tim Sheehy (who's now expected to easily win Tuesday's GOP primary and face off against incumbent Democratic Sen. Jon Tester). Rosendale then announced that he'd seek reelection, but he rapidly backtracked on that decision, too, and instead chose to retire.

A crowded field of Republican contenders has taken shape in the race to succeed Rosendale, including three politicians who hold or have held statewide office: Montana state Auditor Troy Downing; former Rep. Denny Rehberg, who represented the state's old at-large district for six terms until he lost a Senate race in 2012; and state Superintendent of Public Instruction Elsie Arntzen. Downing has built a big fundraising edge — he's raised $1.8 million, of which a little over $1 million has come out of his own pocket. Arntzen and Rehberg, meanwhile, have raised $871,000 and $602,000, respectively, with both candidates having self-funded at least three-quarters of their totals.

Downing, who was elected as state auditor in 2020 after a failed Senate campaign in 2018, appears to be the favorite here. He's been the principal spender on advertising— as of May 15, he'd made more than $850,000 in outlays for media and digital ad buys. Downing has pitched himself as a conservative Trump supporter and critic of Biden's immigration policies. By comparison, Arntzen has spent about $375,000 on ads to argue that she's stood up to "Biden's woke agenda" and wants to deport undocumented immigrants. She has tried to position herself as the most conservative choice, promising to join the hard-right House Freedom Caucus if she wins. Rehberg has promoted himself as an experienced hand, but his campaign seems skeletal in nature: Two-thirds of his expenditures have been to pay back a large chunk of what he loaned his campaign, he's spent only around $100,000 on media buys and his campaign's website is very bare-bones.

The polling we've seen here suggests that Rehberg got off to a strong start, likely due to his name recognition, but it's Downing who's been gaining. An early February survey by Moore Information found Rehberg leading the field, which reportedly encouraged his comeback bid. More recent surveys have found Downing in the lead, albeit from pro-Downing sources. A mid-April survey by Guidant Polling & Strategy for Downing's campaign found him at 38 percent and Rehberg at 26 percent, with Arntzen well back at 10 percent. And an early May poll by Cygnal for the pro-Downing group Elect Principled Veterans gave him a 28-percent-to-12-percent lead over Rehberg, with Arntzen in the single digits.

CORRECTION (June 18, 2024, 5:17 p.m.): A previous version of this article misspelled Montana Sen. Jon Tester's first name as John.