A reminder: on July 3, 2020, the RCP generic ballot average was D+10.5. The final national House vote ended up being just D+2.1. A lot can change in the next four months in either direction.

As polls close in California, here’s a briefing on what to expect tonight: First and foremost: be patient. California is one of the slowest-counting states in the country. We expect only about half of all votes cast in this election to be counted by 7:00 a.m. ET on Wednesday morning. Under California law, mail ballots postmarked by Election Day can arrive up to seven days later and still be counted. Accordingly, we may not know tonight which candidates have advanced to the runoff in either the California gubernatorial race or the Los Angeles mayoral race tonight. California is unusual because it uses a top-two primary system. All candidates, regardless of party, compete on the same ballot, and the two highest vote-getters advance to the general election. The most important dynamic to be aware of tonight is the difference between the votes reported on Election Night and the votes counted afterward. The partisan composition of returned mail ballots is substantially more Republican than it was at this point in 2022. But ballot return data tells us who has voted so far, not who will ultimately vote. There is a meaningful possibility that ballots counted after Wednesday morning, what we often call "the trail," will be considerably more Democratic than the votes reported on Election Night. Why? California generally counts ballots in the order they are received. Republicans appear to be returning ballots earlier than Democrats this cycle. (1) When controlling for past voting behavior, there are still disproportionately more high-propensity Democratic primary and midterm voters who have not yet returned ballots than high-propensity Republican voters. (2) At the same time, Democrats have generally performed well in turnout across primaries held elsewhere this year, making a dramatic statewide Democratic turnout collapse within the realm of possibility but unlikely. (3) We also know that ballot returns have become progressively more Democratic as Election Day has approached. These three factors indicate the remaining uncounted ballot pool could look quite different from the voters represented in tonight's early returns. The key question is how large that shift could be. For example, if Wednesday morning Steve Hilton is at 25% and Tom Steyer is at 21%, can Steyer still catch him? Maybe, maybe not. We need to wait. The race would remain highly uncertain and likely uncallable. In Merced County, the final pre-Election Day report I received showed roughly 22,000 returned ballots from an electorate that was only R+1 by registration, despite the county itself being approximately D+10 by registration. In 2026 across the country, Democratic turnout in primaries has often exceeded what raw registration figures alone would suggest. Even if Dems fall slightly short here, that would still be a 10 point shift towards Democrats after late-mail ballots. This would not be unprecedented. In CA-27 in 2024, Republican Mike Garcia led Democrat George Whitesides by 2.4 percentage points on Wednesday morning. By the time all ballots were counted, Whitesides had won by 2.7 points. So, a 5.1 point shift towards Dems in the trail. This year we could see swings of comparable, or even greater, magnitude. Bottom line: exercise caution when interpreting California results tonight. Early returns may provide valuable information, but they are unlikely to represent the final electorate and the "trail" is hard to predict. We likely won’t know very much by midnight ET, and the picture may still be unclear by 7:00 a.m. ET on Wednesday. We'll know more Wednesday evening, when counties begin reporting batches of votes from the trail. By around 10:00 p.m. ET, we should have a much better sense of how “the trail” is shaping up.