As of Monday, November 4th, 83 million Americans had already cast their votes in the 2024 election. On Tuesday, November 5th – Election Day – millions more will join them.

Your voices will be more important than ever this year: According to 538 projections for the White House, the U.S. Senate and the U.S. House of Representatives, control of the federal government is incontrovertible. Our latest model runs (released November 5 at 6 a.m. Eastern) give Republicans about a 9 in 10 chance of winning control of the Senate, with both the House and the presidency tied. The race for the White House may actually be the closest presidential election in over a century.

The Presidency

Let's start with the race that everyone is watching. According to the final presidential forecast of 538, Vice President Kamala Harris has a 50-in-100 chance of winning the Electoral College after all the votes are counted (which could take a few days). We give former President Donald Trump a 49 out of 100 chance of winning.* In practical terms, these odds are virtually indistinguishable – kind of like flipping a coin and winning heads versus tails.

Statistically speaking, there is also no significant difference between a 50/100 chance and a 49/100 chance. Small changes to the available query data or settings of our model could easily change a 50-in-100 edge to 51-in-100 or 49-in-100. That means our overall characterization of the race is more important than the exact probability — or which candidate is technically “ahead.”

More than any other factor, our forecast is so close because the polls are so close. According to our final polling averages, the gap between Trump and Harris is 2.1 percentage points or less in all seven swing states. Trump currently leads by 2.1 points in Arizona, 0.9 points in North Carolina, 0.8 points in Georgia and 0.3 points in Nevada. Harris is up 1.0 points in Wisconsin and Michigan. And in Pennsylvania (the state most likely to decide the outcome of the election), Harris has a tiny lead of 0.2 points.

However, it must be emphasized that the polls will not be entirely accurate. For example, polls overestimated Democrats by an average of 3 to 4 points in both the 2016 and 2020 presidential elections and overestimated Republicans by an average of 2.5 points in the 2012 presidential election. Our election model assumes that the polls are off by an average of 3.8 points this year, although it could be more or less – and our model assumes that this error is just as likely to favor Democrats as Republicans.

In other words, you shouldn't expect polls in presidential elections to be completely accurate. You should assume that they are just as imperfect as they were in the past. And in a race with very slim advantages for the leader in each key state, that means there is a wide range of possible outcomes in the election.

And that's why we said that just because the polls are, the race won't necessarily be close. Our model says Trump and Harris are both one normal polling error away from failing in the Electoral College. If we shift the polls 4 points toward Harris, she would win the election with 319 Electoral College votes:

Meanwhile, Trump would win by 312 electoral votes if polls underestimated him by the same amount:

Hopefully you can see how uncertain a 50-100 chance of winning the election really is. When we say the race for the White House is a back-and-forth race that can go either way, we mean it.

The House of Representatives

In the 2022 midterm elections, Republicans managed to regain the majority in the US House of Representatives. But they fell well short of historical expectations, particularly in seats where their candidates contested the results of the 2020 election. In the end, they won only 222 seats – barely enough to have a functional majority (and sometimes it wasn't even that functional).

According to 538's final House forecast, the Republican Party is in real danger of losing the chamber entirely in 2024. We give them a 49 in 100 chance of controlling the House, while the Democrats have a 51 in 100 chance of taking control. But whichever party wins the majority could find that it is so narrow as to be ungovernable: The median outcome of our forecast is for Democrats to win just a one-seat majority.

However, there is also considerable uncertainty here. Because House polls are subject to a lot of error and the other indicators used by our House can be highly biased, our model assumes that the probability of a party receiving a double-digit majority is about 1 in 2.

To achieve a double-digit majority, Democrats would need to win all of the seats our model classifies as Likely Democratic, Lean Democratic, and Toss-up, and secure two of the 23 seats we currently classify as Lean. or “Likely Republican.” Conversely, Republicans would have to win all of their “likely” and “lean” seats, all of their “toss-ups,” and four seats where Democrats are currently favored. Such achievements sound ambitious, but it is common for parties to eliminate most or even all of the mistakes when they exceed expectations.

One final point where surprises are to be expected. We already know we won’t pick the “right” winners in every seat. This is intentional. Our goal is not to pick winners; It's about correctly assessing probabilities. And for us to be successful in this regard, candidates with a 75 out of 100 chance of winning must win 75 out of 100 – and lose 25 out of 100. Our final forecast is for 66 seats to be toss-up. “Lean” or “Probable”. Based on how well our model would have predicted similar elections in previous elections, we expect 14 of these districts to go to the party that is not considered the favorite to win. Additionally, we expect three upsets in districts rated “solid” for both parties — meaning they have at least a 98-100 chance of winning.

The Senate

And now to the race that is definitely not close: the race for control of the Senate. Our model gives Republicans a 92-in-100 chance of winning control of the upper chamber, including scenarios in which they win 51 seats or more and scenarios in which they win 50 seats plus the White House (the Vice President breaks the tie). in the Senate).**

The Republicans' strength in our forecast comes from their expected victories in reliably red Montana and Ohio, where moderate Democratic incumbents are trying to fend off strong Republican competition. In Montana, the GOP has a 93-100 chance of defeating Sen. Jon Tester. In Ohio, Senator Sherrod Brown has a 41 in 100 chance of defeating Republican businessman Bernie Moreno. And our forecast gives West Virginia Democratic candidate Glenn Elliott just a 1 in 1,000 chance of retaining outgoing Sen. Joe Manchin's seat.

If Democrats lose at least two of those seats, which we predict will happen about 95 percent of the time, they will need to secure a seat elsewhere to maintain their majority. According to our forecast, they have the best chance of doing so in Florida or Texas, but they only have a 16 in 100 chance of winning in each case. That's not nothing; It's about the chance of rolling a normal six-sided die and getting a 1. But it's still a pretty steep climb for Democrats.

Our final word

This is a good time to remind people that our forecasts are not crystal balls. And especially in a year when the races are so close together, they cannot provide greater certainty than the data we have. As I wrote last week, building election prediction models is not about providing a high-precision, laser-like predictive picture of the election that removes all doubt about what might happen. It's more about giving people a good understanding of how the polls could be wrong and what would happen if they were wrong.

Both parties could be ahead in the presidential and House elections if poll numbers deviate from historically normal levels. In the Senate, polls would have to be more off in at least one state than they were in 2020. That's possible, but given the other information we have about the seats up for grabs, we think it's unlikely that Democrats will hold the chamber.

Footnotes

*Technically, Harris has a 50.33 percent chance of winning and Trump has a 49.45 percent chance of winning, and there is a 0.22 percent chance of a tie in the Electoral College. For this reason, the rounded numbers do not appear to add up to 100 percent.

**As well as scenarios in which Republicans win 50 seats and independent candidate Dan Osborn of Nebraska wins his seat and chooses not to caucus with either party.