In several of California's open congressional districts, tonight could be the end of any suspense about who the next representative will be. Or, it could be the start of an eight-month intraparty slog.

That's because California's unique all-party primary system — where the top two primary vote-getters advance to the general election — allows for either a traditional contest between a Democrat and a Republican or a fight between members of the same party in the general election, and it's not always obvious which one you're going to get. That's the case in at least four open-seat races today — three Democratic and one Republican.

In California's 16th District, there are nine Democrats but just two Republicans vying to replace Democratic Rep. Anna Eshoo. While limited polling of the district suggests that former San Jose Mayor Sam Liccardo or Santa Clara Supervisor Joe Simitian, both Democrats, are the front-runners, if one of the two Republicans consolidates most of the GOP vote and the Democratic vote scatters among the many candidates, a Republican could finish in the top two. In the 2022 primary, the Republican candidates didn't meet that threshold, splitting a combined 22 percent of the vote; the four GOP candidates in the state's Senate race won a combined 24 percent in the district. A Republican advancing would ensure that whichever Democrat also finished ahead would win the general election in November, given the district's partisan bent. But if two Democrats finish in the top two, it'll be a real race.

Same goes in the 30th District, where Adam Schiff is leaving to run for Senate. Twelve Democrats and just two Republicans will appear on the ballot there. In the 2022 primary, four GOP House candidates totaled 21 percent, and Senate GOP candidates combined for a smaller 22 percent. Democratic state legislators Anthony Portantino and Laura Friedman, and Democratic former city attorney Mike Feuer are the front-runners for this seat; if two of those three make it to the general election, it will be an expensive and sharp-elbowed race to November, but if one of the Republicans squeezes in, it's basically over.

In the 31st District, where Democrat Grace Napolitano is retiring, six Democrats and two Republicans are running. In 2022, the one Republican running for the seat, Daniel Martinez, advanced to the general by winning 37 percent of the vote in the primary. Former Rep. Gil Cisneros, state Sens. Susan Rubio and Bob Archuleta, former Monrovia Mayor Mary Ann Lutz and attorney Greg Hafif are all running well-funded Democratic campaigns, creating the possibility that Martinez, who is running again, could finish in the top two instead of two Democrats, effectively ending this race tonight.

And in Kevin McCarthy's old seat, the 20th District, it's a similar story with the parties reversed. There, the two Democrats will probably combine for around 30 percent of the primary vote (in 2022, the House candidates combined for 30 percent and the Senate candidates for 32 percent), while six Republicans fight over the remaining 70 percent (a seventh dropped out but remains on the ballot).

—Jacob Rubashkin, Inside Elections

Although the race has mostly gone as expected, with Trump securing most of the delgates in the first several GOP nominating contests, Republicans still say they are paying attention, according to a February Echelon Insights survey. Seventy-nine percent of Republican likely voters in the survey say they are paying a lot of or some attention to the race, while just 20 percent say they’re paying only a little or no attention at all. Among those who aren’t tuning in, 36 percent say the number one reason is because they’re tired of politics, while 17 percent say it’s too early and 15 percent say they don’t think the race is competitive.

—Mary Radcliffe, 538

On Sunday, Republicans in Washington, D.C., voted for Haley by nearly 30 percentage points in the GOP's party-run primary, giving her all 19 national delegates from the nation's capital. This marked her first victory anywhere in this year’s primary contest, and the first ever primary or caucus victory for a woman in the history of Republican nomination races. Yet the other contests that took place just ahead of Super Tuesday otherwise showcased Trump's strong hold over his party's base. This included victories on Saturday in caucus-convention races in Idaho, Michigan and Missouri, and in North Dakota's Republican caucuses on Monday.

In Michigan, Republicans gathered at Saturday's state party convention to allocate 39 national delegates from the state’s 13 congressional districts (three per district). The voters consisted of precinct delegates mostly elected at the August 2022 state primary as well as Republican elected officials, and they handed Trump all 39 district-level delegates. This result brought Trump's Michigan haul to 51 of the state's 55 delegates, after he had already won 12 of its 16 at-large delegates in the Feb. 27 primary.

The Michigan GOP's split primary-caucus approach came about in part because national Democrats added Michigan to the early part of their presidential primary calendar, prompting the Democratic-controlled state government to shift the state’s primary date into late February. Since the new date violated the national GOP's calendar rules, Michigan Republicans used a workaround whereby the primary results would allocate the state's at-large national delegates, but the state party didn’t formally make the allocation until March, at Saturday’s caucus-convention that also allocated district-level delegates.

Trump also swept caucuses in Idaho and Missouri on Saturday, and then North Dakota on Monday. In Idaho, Trump won 85 percent of caucusgoers, easily surpassing the state's 50 percent winner-take-all threshold to capture all 32 of Idaho's national delegates. In Missouri, Trump won every state- and congressional district convention delegate elected at local caucuses around the state, all but guaranteeing that he will sweep all 51 national delegates when the district and state conventions formally allocate delegates in April and May, respectively. And in a near-repeat of Idaho, Trump won 84 percent of caucusgoers in North Dakota on Monday to claim all 29 of the state’s national delegates.

—Geoffrey Skelley, 538

Based on each state's politics and demographics, 538's G. Elliott Morris has calculated how many delegates both Trump and Haley need to win in each state today to be on pace for the nomination. Here are those numbers:

In total, Trump's magic number tonight is 497 delegates, while Haley's is 543. Elliott's model thinks Trump needs to sweep Arkansas, California, Tennessee and Texas while also taking about half of the delegates available in Alaska, Colorado and North Carolina. Meanwhile, if she wants to have a shot at winning the nomination, Haley must win all the delegates in Alabama, California, Maine, Massachusetts, Minnesota, Oklahoma, Utah, Vermont and Virginia — a tall order on a night where winning even one state isn't a certainty.

—Nathaniel Rakich, 538

Tonight, I'll be paying close attention to the results coming in from Alabama's GOP presidential primary.

That's not because there is much doubt about the outcome. Against stiffer competition in 2016, Trump carried every county in this Republican-dominated state, winning by 22 percentage points statewide. In 2024 primaries so far, Trump has tended to do well not only in places where he did well eight years ago, but also in places where Ted Cruz, the leading candidate among more conservative and evangelical voters, did well. Since Cruz finished second in Alabama in 2016, it's not a very promising state for Haley.

But even without much question about who's going to win statewide, Alabama serves as a bellwether for the state of today's Republican Party. It's the state with the highest population share of evangelical Protestants nationwide, a focal constituency of the contemporary GOP. Alabama has also been home to several competitive GOP primaries in recent years that can jointly tell us a lot about competition in the party today. Even after Trump's rise to the top of the party in 2016, precinct-level returns in Alabama's Senate primaries make clear that there aren't consistent pro-Trump and anti-Trump blocs going head-to-head in election after election. Instead, GOP candidates in recent Alabama primaries have put together somewhat idiosyncratic geographic coalitions.

Consider 2017, when appointed U.S. Senator Luther Strange, who had the backing of both Trump and the GOP establishment, competed against judge Roy Moore in a special election for the GOP's Senate nomination. Despite accusations of child sexual abuse, Moore prevailed over Strange in the primary (before losing to Democrat Doug Jones). New research suggests that in that primary, precinct-level support for Moore was higher in places where Trump and Ben Carson had done better in 2016, but the correlations are pretty modestly sized. In other words, knowing where Trump did better in 2016 really didn't have much predictive power in the next year. Still, Marco Rubio's 2016 vote share was negatively associated with Moore's, meaning those two candidates drew support from different places.

2020 may provide a clearer test: Trump's first supporter in the U.S. Senate and subsequent attorney general, Jeff Sessions, was running to take back his old seat, but Trump and Sessions had since fallen out and Trump instead endorsed the eventual winner, Tommy Tuberville. The places that had backed Trump in 2016 were somewhat less supportive of Sessions in 2020. Still, these correlations were pretty modest, and Trump's 2016 support also wasn't strongly correlated with backing either of Sessions's major opponents, Tuberville or Bradley Byrne.

And in the 2022 Republican Senate primary, Trump support was slightly negatively associated with 2022 support for both Rep. Mo Brooks, the conservative whom Trump unendorsed during the campaign, and eventual winner Katie Britt, who he did endorse. Trump's 2016 vote was only somewhat positively correlated with support for Mike Durant, a helicopter pilot who was shot down in Somalia as part of the battle depicted in "Black Hawk Down." But like 2017 and 2020, the 2022 Republican primary was not just a rerun of 2016.

Now, with Trump himself on the ballot, it's a different story. I expect that Trump will do very well in the parts of Alabama that he dominated in 2016 (read: most of the state), and that Haley's vote margins will be slightly stronger around Birmingham and Huntsville, just as Rubio did eight years ago. This was true in New Hampshire, for example, where Trump's 2016 precinct-level vote share was correlated with his 2024 vote share at 0.63, a strong correlation given the very different competition he faced in the two years. But, as a close look at Alabama primaries in recent years shows, Trump's 2016 supporters haven't necessarily formed a cohesive voting faction. During the Trump era, when Trump is not on the ballot himself, voters haven't always hewed closely to the divisions he has fostered.

—Dan Hopkins, 538 contributor