While we can’t be certain who will win the presidential election, we can predict one thing with a high degree of confidence: Donald Trump will claim he won. And he’ll probably do this on Tuesday night. I want to lay out why it’s important not to jump to conclusions about who is winning, and instead prepare for the vote counting to take a few days — at least.

In 2020, it took four days after the polls closed for the race to be called for Joe Biden. This was a slower count than usual, and for good reason: Many states had expanded their use of early and absentee voting due to the pandemic, and it can simply take longer to count all those ballots. On top of that, voter turnout was unusually high — 158 million people voted, nearly 22 million more than had voted four years earlier.

One of the patterns we’ve seen in recent elections will likely occur this year as well.

It’s unlikely that the vote counting will take quite as long this time. States have become more efficient at counting early and absentee ballots, and a number of states have scaled back the accessibility of such votes. Also, simply because Covid is no longer as much of a threat, more people are voting in person this year.But one of the patterns we’ve seen in recent elections will likely occur this year as well: the “blue shift” (or “red mirage”). In many states, in-person votes get counted before early and absentee ballots do. Thanks in part to Trump’s disparaging of mail-in voting in recent years, Democrats are more likely to cast an early vote than Republicans are.

What this means is that the first results reported on Tuesday evening are likely to trend a bit Republican, then swing toward the Democrats as the mail-in ballots are totaled. Now, that doesn’t matter for the final count, but it could affect how the media covers the counting. As he did in 2020, Trump will use the early Republican-leaning vote count to try to claim that he has won and that later votes coming in for Harris are signs of malfeasance. This is definitely not true! But it will likely be the basis of lawsuits he files. He is already claiming fraud and the election hasn’t even happened yet.

Now, there’s no guarantee this will go on for very long. Right now, the polls suggest that the swing states are basically tied. It’s pretty likely that the polls are off by 1 or 2 points — this is historically pretty normal — and they’ll probably be off in the same direction across different states. Which means there’s a plausible chance that either Harris or Trump will win most or all of the swing states. If it looks like it’s heading that way on Tuesday night, we might not need many days to figure this out. We could even wake up the next morning with a new president-elect.But chances are we’re going to be focusing on a handful of states overnight Tuesday. I want to mention four that are likely to be both close and slow:

Pennsylvania is the big prize this year. Its 19 Electoral Votes make it very likely that whoever wins the state will become president. But under state laws, election workers will not process any ballots — including the early and mail votes — until the polls close at 8:00 p.m. ET. Given how close the election appears right now, it could take a day or two to call the state.

Arizona, with 11 electoral votes, has an unusually long ballot this year, which could delay vote counts. And the mail-in ballots received on Election Day won’t be tabulated until after the polls close that evening. Once the state starts counting it tends to move pretty quickly, but most outlets did not call the state in 2020 until more than a week after the election, so it may be hard to call it on Tuesday night.

Michigan, with 15 electoral votes, could also take a while. The state spans two time zones, with the Upper Peninsula not closing its polls until 9:00 p.m. ET.

Nevada, with six electoral votes, took several days to be called in 2020, and a new law allows ballots postmarked by Election Day to be counted if they’re received up to four days after the election is over. Again, if the election is very close, this state could be tough to call.

As we watch the votes get tallied, it will be useful to observe how voting patterns differ from four years ago. That and exit polls can give us an idea of how things are going to develop as the counting goes on.But chances are, we’ll just need to be patient. Yes, we’ll want to know quickly, and yes, Trump will try to exploit the uncertainty for his own ends. But it’s really just a matter of counting the votes. And the time that it takes to finish the task is evidence that the counters are taking their job seriously.

Seth Masket

Seth Masket is a professor of political science and director of the Center on American Politics at the University of Denver. Follow his Substack at https://smotus.substack.com/.