Can Haley stop a Trump sweep on Super Tuesday?

They don't call it "Super Tuesday" for nothing. On March 5, 15 states will hold their Republican presidential nominating contests, the most action-packed day of the primary yet. For all the attention given Iowa, New Hampshire and their early-voting ilk, only 331 delegates to the Republican National Convention will have been chosen heading into Tuesday — a mere 14 percent of the total. But on March 5 alone, 854 delegates (35 percent of the total) are up for grabs.

If there is suspense in the presidential race on Tuesday, though, it's not about who is going to win the most states or delegates — it's about whether former President Donald Trump will go 15 for 15. Regardless of whether he completes the sweep, with his massive lead in the polls, Trump is very likely to emerge from Super Tuesday on the cusp of mathematically clinching the Republican nomination, which he can do as early as March 12. But for inveterate election watchers like us, there are a few contests that former U.N. Ambassador Nikki Haley has a shot at winning.

There are enough polls for 538 to calculate a polling average* of six of the 15 states voting on Tuesday: California, Massachusetts, North Carolina, Tennessee, Texas and Virginia. As of 1 p.m. Eastern on Monday, Trump leads Haley by at least 37 percentage points in each of them:

Trump also leads by at least 42 points in the few polls we have this year from Alabama, Maine, Minnesota and Oklahoma. His lead is smaller, though still substantial, in the most recent surveys of Utah (27 points) and Vermont (30 points). There have been no polls of Alaska, Arkansas or Colorado in months, if at all, but based on what polls say in demographically similar states, we believe Trump has solid leads in them as well.

However — and we almost never say this — the polls may not be the most reliable on Tuesday. Unlike Iowa, New Hampshire and South Carolina, which were the focal points of the political world in the days leading up to their contests, the Super Tuesday states haven't been polled very much in recent weeks, which means that we're basing our perceptions of them on pretty stale data. In fact, the only polls of these states conducted entirely within the last month were three polls of California, two of Maine, three of North Carolina, one of Texas, one of Vermont and one of Virginia. Otherwise we're flying blind.

It's also possible that the polls could be overstating Trump's advantage in some of these states. Up until the Michigan primary last Tuesday, the polls had been pretty close to the mark on Trump's share of the vote, but had tended to exaggerate his margin. But then Michigan surveys substantially overshot Trump's position across the board, as the table below shows.

Now, primary polling is more challenging than surveying a general election. Over the past quarter century, the average error in presidential primary polls is about 9 points, whereas it's been closer to 4 points in general election polls. Primaries are more dynamic because, unlike in a general election, a voter (for the most part) isn't simply picking between a Democrat and a Republican. Candidates may drop out during the nomination race and leave polls with less time to capture how voter sentiments have shifted before the next contest.

Additionally, it's not easy for pollsters to nail down what the electorate will look like. For example, some Democratic-leaning independents may be voting this year in the GOP primary because President Joe Biden is a shoo-in to win renomination — and it's likely that most are not voting for Trump. (Helpfully for non-Republicans, Michigan and South Carolina are open primary states with no party registration that allow anyone to vote in one or the other party primary, while New Hampshire permits unaffiliated voters to participate.)

Which states might be Trump's strongest — or weakest?

With the potential for error in mind, we dug further into three factors that could loom especially large in each race: whether a GOP contest permits non-Republicans to vote, how highly educated the electorate is and the religious identity of voters. Thus far, Trump has done best with primary voters who identify as Republican, winning 70 percent or more of them in New Hampshire and South Carolina, per the exit polls. He's also done better among those who don't have a four-year college degree (67 percent or better in those two states) or identify as white evangelical Christians (70 percent or more).

Conversely, Haley has done much better among independents (winning around 3 in 5 of them in New Hampshire and South Carolina), college graduates (winning with narrow majorities) and voters who didn't identify as white born-again Christians (garnering between 45 and 55 percent). Fundamentally, her struggles among self-identified Republicans will make it difficult for her to win anywhere on Super Tuesday, since they'll unsurprisingly make up a majority of GOP primary voters pretty much everywhere. But she could do better in some more highly educated and less religious states that permit non-Republicans to vote.

Considering all this, we've laid out the voter access rules for each Super Tuesday contest, the share of the population that is white with a college degree or not and the share that is white evangelical Christian (most voters participating in GOP primaries will be white).

Given his strengths, Trump should rack up huge percentages in the South on March 5. His four best states might be Alabama, Arkansas, Oklahoma and Tennessee, all of which have white populations that disproportionately have less than a four-year degree and rank in the top 10 states based on white evangelical Protestant population share, according to the Public Religion Research Institute. Per the 2016 exit polls, around 7 in 10 GOP primary voters in these states identified as white evangelical, and 4 in 5 were very or somewhat conservative — also solidly pro-Trump categories in 2024. The South's population characteristics tend to overshadow the fact that many states there allow any voter to participate in party primaries.

Trump should also do quite well in Texas and North Carolina, two larger Southern states that also have sizable shares of white voters who are not college grads or who identify as evangelical Christian. Texas's overall population is majority-minority, and it had just about the most ethnically diverse electorate of any Republican contest in 2016, according to the exit poll. Still, 4 in 5 primary voters there identified as white. About 7 in 10 GOP voters in both Texas and North Carolina identified as Republican back then, while a larger share of North Carolina voters said they were white born-again Christians in 2016 (63 percent) than in Texas (51 percent).

California will likely vote strongly for Trump, too. We don’t have a Golden State primary exit poll from 2016 — California voted in June after the GOP race was effectively over — but because the state will use a closed primary, we do know that the primary voters will mostly be Republicans.

Similarly, we can probably expect Alaska and Utah to substantially favor Trump because Republicans in each are using party-run events to vote — essentially a party-run primary in Alaska and caucuses in Utah. These lower-turnout events will involve only registered Republicans, and they attract the most committed party members who tend to be even more conservative. Now, Utah might not be a complete blowout because Republicans there have demonstrated more lukewarm attitudes toward Trump. But Utah likely would've been more interesting had Republicans used the state's presidential primary, which is also happening March 5 (Democrats are using the primary). Utah Republican caucusgoers have had a habit of being far more conservative than the wider GOP primary electorate.

Maine and Minnesota may also produce fairly robust wins for Trump, although Maine’s primary will be open to unaffiliated voters for the first time and Minnesota uses an open primary system. Both states have sizable shares of white voters without a four-year college degree relative to the share that has one, which will likely favor Trump. In Maine, Trumpy candidates like former GOP Gov. Paul LePage have seen success. However, Maine and Minnesota used caucuses back in 2016, so we don’t have a recent record of their primary electorates to look at.

By comparison, Colorado, Massachusetts, Vermont and Virginia could be Trump's worst states. To be sure, he's favored to carry all four, but each has features that could boost Haley. The Northeastern duo has few white evangelical Christians, moderating their primary electorates, and each makes it possible for non-Republicans to vote. And all four states have a sizable share of white voters who are college grads. In fact, a majority of Colorado's white population has at least a bachelor's degree. Both Colorado and Virginia are also more accessible to non-Republicans, and Virginia ranked as one of Trump's weakest states in the South in 2016.

Even if the polls do overshoot Trump's position in some contests, Trump looks positioned to enjoy a Super Tuesday sweep. That outcome would make Haley's position in the Republican nomination contest even more untenable than it already is — if her goal is finding any path to victory. She's only promised to stay in the race until March 5, so it remains to be seen what she'll choose to do moving forward.

Footnotes

*538 calculates a polling average for a given election when we have collected at least eight different polls of it from at least three different pollsters.

CORRECTION (March 5, 2024, 11:19 a.m.): A previous version of this article and a table in the article incorrectly stated that Minnesota is a closed primary state. The article and table have been updated to reflect that Minnesota is an open primary state.