The race in California's 47th District is competitive within the Democratic field where, as we've mentioned, Rep. Katie Porter decided to run for Senate, opening up her House seat. The House primary she won in 2018 to face (and eventually defeat) the Republican incumbent, Mimi Walters was also competitive. In fact, Dave Min, who is running today, was the favored Democrat in that 2018 primary, but Porter beat him out to finish second, behind Walters, and went on to win the seat. With 46 percent of the expected vote in, Min is leading his closet rival, Joanna Weiss, by about 8 points.

—Meredith Conroy, 538 contributor

Redistricting made Alabama's 2nd District Democratic-leaning, and a bevy of candidates jumped into the party primary with a shot at winnable seat. But in Alabama, primary winners must win a majority, so the crowded race has made an April runoff likely. With about 80 percent of the expected vote reporting, former Justice Department official Shomari Figures leads with nearly 44 percent. ABC News has projected that Figures, the son of longtime state Sen. Vivian Figures and the late state Sen. Michael Figures, will advance to the likely runoff. The race of the second runoff spot is not set, but state House Minority Leader Anthony Daniels has 22 percent, ahead of state Rep. Napoleon Bracy's 16 percent. Daniel actually hails from Huntsville in the north of the state, far from the southern Alabama base of the district. Bracy is from Mobile, and there are still some votes left to report from there, so he can't be discounted.

—Geoffrey Skelley, 538

I just want to underscore Elliott's point about how hard polling has gotten with a quick story I wrote up in a paper with Tori Gorton called "On the Internet, No One Knows You're An Activist." We were trying to survey lower-engagement voters, so we drew a sample of 9,937 registered Pennsylvania voters who hadn't consistently voted 2012-2018. Then, we matched them to Facebook accounts and served ads to 1,321 inviting them to take a survey. 66 people clicked on our ad, 7 began the survey, 6 completed it, and 1 person left an email for follow-up. I of course want to express my deep gratitude to that one respondent. But beyond that, a 0.4% response rate magnifies sampling errors, because very small differences in people's willingness to take polls can add up to very large errors in vote margins. That's especially true in primaries, where pollsters can't use partisan identification to stabilize the results.

—Dan Hopkins, 538 contributor

We've been tracking Trump's non-incumbent endorsees (because endorsing the incumbent is kind of a gimme) tonight, and so far he's 4 for 4 of the races called. Addison McDowell, Trump's pick in North Carolina's GOP primary for the 6th District, is also leading. But in California, state Assemblyman Vince Fong, who received Trump's endorsement for the Republican primary in the state's 20th District (Kevin McCarthy's old seat), is trailing at 26 percent with 23 percent of the expected vote reporting.

—Kaleigh Rogers, 538