We're still waiting on results in most races, but I'm also watching Oklahoma, where polls have just closed. Trump has a massive lead against Haley in recent Republican primary polling in Oklahoma, and, since the primary is closed, Haley can't count on independents and Democrats shrinking his margin against her. Trump won the state in the 2020 general election with 65 percent of the vote, making it one of his best states in the U.S., and Biden did not win a single county there.

Heavily evangelical, with a mix of Southern and Western spirit, Oklahoma remains one of the reddest states in the country. Whoever wins this primary race is almost certain to carry the state in November. Sen. Markwayne Mullin, the state's junior senator, has called on Haley to drop out if she doesn't win a single state tonight.

—Monica Potts, 538

The 2024 primary season has been weirder than I think anyone expected. The two parties feel like they have a lot of internal tension, but with a current and a former president seeking their parties' respective nominations, it hasn't been very competitive. One result of this has been that we've been looking for clues to the general — the Trump-Biden rematch — in the primary results. In turn, this has meant some overinterpretation of primary results — it's not a given that people who cast a vote for another candidate won't come home in the general.

It's also hard to compare the internal dynamics of the two parties and apply those to predictions for the general. Dean Phillips' candidacy, for example, has presented himself as a moderate, pragmatic alternative to Biden — but he's mostly emphasized the age difference. Some Democrats have been unhappy with the policies of the administration, especially on the Israel issue, but there hasn't been a progressive candidate to challenge him. Trump, on the other hand, has faced — and beaten — experienced opponents with more substantive disagreements. This makes it harder to use the primary as a direct roadmap to what the candidates' liabilities might be in the fall.

—Julia Azari, 538 contributor

While we're on the topic of Vermont politics (and books), I can't recommend Frank Bryan's book Real Democracy highly enough. Over decades, Bryan sent college students to attend town meetings throughout Vermont, where local residents make key decisions in a form of direct democracy that's uncommon elsewhere. The product is a highly readable book with plenty of local color about direct democracy in Vermont's towns.

—Dan Hopkins, 538 contributor

Ha, Jacob, to that point: If anyone is interested in some Vermont political history, here are a couple recs from someone who recently moved to the state (me). There's "The Star That Set: The Vermont Republican Party, 1854-1974," which lays out the rise and dominance of the GOP in Vermont, then its decline in the latter half of the 20th century as the state became two-party competitive. And "Philip Hoff: How Red Turned Blue in the Green Mountain State" investigates the changes in Vermont during the 1960s that surrounded Democratic Gov. Philip Hoff, the first Democrat to win Vermont's governorship after the Civil War. (This ends the Vermont Book Club portion of the evening.)

—Geoffrey Skelley, 538

Minnesota Rep. Dean Phillips ended his campaign for president today and endorsed Biden's reelection campaign. Phillips got into the race last fall, citing Democratic worries about Biden's age and ability to beat Trump. But his campaign never took off, even in New Hampshire, where he focused much of his efforts because Biden wasn't on the ballot due to the state's primary having violated the national Democrats' new calendar rules. Phillips won 20 percent of the New Hampshire vote, but he didn't clear 10 percent in any other state where he got on the ballot. Yesterday, he earned 8 percent in his home state of Minnesota and 9 percent in Oklahoma, his best showings otherwise.

Although some Democrats share Phillips's concerns about Biden, Phillips predictably struggled because the incumbent president remains relatively well-liked by those in his party. Phillips was an unusual primary challenger in that he didn't have sizable ideological disagreements with Biden that stoked his run — the moderate congressman was not from the Bernie Sanders wing of the party, for instance. And Phillips's overall performance reflects the lack of appetite for a center-left alternative to Biden — who hails from that part of the party — or at least one who didn't already have a sizable standing. Rather, the intraparty dissatisfaction with Biden has been felt more on the left, which has been especially critical of Biden's handling of the Israel-Gaza situation. (See: the "Uncommitted" protest movement getting more votes than Phillips in his home state.) Tellingly, Marianne Williamson's minor left-wing campaign has actually won more votes than Phillips in 10 of the 15 primaries they both participated in.

—Geoffrey Skelley, 538