Rounding out our key House races in Ohio as polls close at 7:30, the Republican primary has been pretty uneventful in another Ohio swing seat: the 13th District, which Biden would have carried by 3 percentage points in 2020. Democratic Rep. Emilia Sykes will likely face either former state Sen. Kevin Coughlin or Hudson City Councilor Chris Banweg in November. Not much distinguishes the two, though: They both support Trump and share the same conservative positions on abortion, immigration, guns and more. And they both have raised only modest amounts of money: $332,000 for Coughlin, $280,000 for Banweg. Sykes, by contrast, has pulled in $1.9 million for her reelection bid so far.

—Nathaniel Rakich, 538

Trump has endorsed only three candidates in seriously contested primaries today: Moreno, Bost and Merrin. With all three locked in competitive races, tonight's results could be a good signal of whether Trump's endorsement is as powerful as it used to be. We'll be tracking these races throughout the night.

—Nathaniel Rakich, 538

One of today's most consequential primaries for the general election is taking place in Ohio's 9th District. According to Daily Kos Elections, Trump would have carried the district 51 percent to 48 percent in 2020. But in 2022, incumbent Democratic Rep. Marcy Kaptur defeated Republican Air Force veteran J.R. Majewski 57 percent to 43 percent here thanks to Majewski's weaknesses as a candidate: He exaggerated his military service, attended the Jan. 6 rally (though he says he didn't enter the Capitol) and once subscribed to the QAnon conspiracy theory.

Majewski quickly announced he would run again in 2024, agitating Republican operatives who feared he would once again throw away a winnable House seat. But to their relief, he withdrew from the race a few weeks ago, leaving the primary to state Rep. Derek Merrin and former state Rep. Craig Riedel. Riedel was originally the top alternative to Majewski, but a couple of his pro-Trump supporters withdrew their endorsement of him after audio leaked of him calling Trump "arrogant." That sent GOP elders scrambling to find a new alternative to Majewski, and Merrin — who was in line to be the speaker of the Ohio state House last year until a faction of renegade Republicans joined Democrats to elect a different Republican — jumped into the race just before the filing deadline.

The primary is far from settled, though. While Trump endorsed Merrin just yesterday, and Speaker Mike Johnson endorsed Merrin in January, many establishment Republicans, such as House Majority Leader Steve Scalise and Majority Whip Tom Emmer, are still with Riedel. And Merrin's late entry into the race means he trails Riedel badly in fundraising, $175,000 to $1.2 million. And while he's no Majewski, a Riedel win could still give Republicans headaches: He's aligned with the tea party movement and has previously expressed interest in joining the hardline House Freedom Caucus.

—Nathaniel Rakich, 538

Chicagoans are voting today on a ballot measure pushed by progressives that would institute a real estate transfer tax to fund programs addressing homelessness. Today's outcome could tell us something about the strength of Chicago's progressive movement … and its unpopular progressive mayor, who's made it a policy priority.

According to publicly available polling, while Chicagoans may have started out feeling good about Mayor Brandon Johnson, their opinion quickly soured. According to Chicago-based Victory Research, Johnson's approval when he first took office in May was at 63 percent. Five months later, in October, Echelon Insights/Illinois Policy Institute found his approval to be just 28 percent, with 50 percent of voters disapproving of his job performance. By January, Tulchin Research/Stand for Children registered an approval rating of just 21 percent, with 70 percent saying his performance was "only fair" or "poor," while Echelon Insights/Illinois Policy Institute marked his approval at 29 percent and disapproval at 57 percent.

The January Echelon Insights survey also asked respondents if they approved of Johnson's handling of various issues facing the city. The mayor received the lowest ratings on "housing and homelessness" (20 percent approve, 68 percent disapprove), "management of immigrants transported to the city" (23 percent approve, 69 percent disapprove), and "crime and public safety" (24 percent approve, 66 percent disapprove).

—Mary Radcliffe, 538

California held its statewide primary for president and downballot races on March 5, but it still gets to join in on the March 19 fun. There’s a special election in the 20th Congressional District to fill the vacancy left by former House Speaker Kevin McCarthy, who resigned his seat at the end of 2023. The solidly red seat is all but guaranteed to elect a Republican, but the main question is whether the special will produce a winner today or necessitate a runoff.

That’s because California special elections don’t work exactly like its regular top-two primary elections. Instead, they operate similarly to Louisiana’s jungle primary system. All candidates, regardless of party, run together in a first round — the race happening today — and if one candidate wins a majority, that candidate is elected. But if no candidate wins a majority, a runoff takes place between the top two candidates. Should no one surpass 50 percent today, the two leading contenders will meet on May 21.

In some ways, the March 5 top-two primary served as a dry run for the special because the leading candidates in that race are also on the special election ballot. The favorite is probably Republican state Assemblymember Vince Fong, who led all candidates with 42 percent of the primary vote two weeks ago. Fong is viewed as McCarthy’s hand-picked successor, and he also has Trump’s endorsement. Fellow Republican Tulare County Sheriff Mike Boudreaux narrowly grabbed the second November spot with 24 percent in the primary, so he’s probably the second-most likely candidate to win or advance to a runoff. But in the primary, Boudreaux only ran a little ahead of Democrat Marisa Wood, who won 21 percent, so she could finish ahead of Boudreaux in the special. This is especially true considering that Republican turnout may not be as high today as it was on March 5 because the special won’t coincide with a much-watched GOP presidential primary.

Differences between the set of candidates running in the special and those who ran in the regular primary could also cause consequential shifts in vote share. Four minor Republicans not running in the special won about 5 percent in the primary, while a minor Democrat not running in the special won about 3 percent. Should this support line up more behind the leading contenders in each party, Fong would find himself closer to a majority to win outright, while Wood might overtake Boudreaux for the second spot in a potential runoff. Moreover, voters know how the primary result played out, so that could influence them to consolidate behind the leading candidates. Still, six other lesser candidates are on the special election ballot, so even if they don’t win much of the vote, what share they do take could still help influence the special’s outcome.

—Geoffrey Skelley, 538