Iowa and New Hampshire have a few things in common. Together, they have started the presidential primary calendar since the modern nomination process took shape in the 1970s. Both states have a long history of prioritizing retail politics, pushing candidates to pursue face-to-face interactions to gain voters’ support. And demographically, each state has a small population that is overwhelmingly white.
Despite these similarities, however, the contrasts between Iowa and New Hampshire have loomed large in Republican presidential nomination contests. Using entrance (Iowa) and exit (New Hampshire) poll data, we can see striking differences between the states’ GOP electorates in terms of party identification, ideology and religious identity. Overall, Republican caucusgoers in Iowa are more conservative and evangelical than GOP primary voters in New Hampshire. This split is due not only to differences across the two states’ populations, but also divergent electoral rules that give New Hampshire a larger, less right-leaning electorate than Iowa.
Thanks in part to these cleavages, the two states have voted for different winners in every open Republican presidential contest dating back to 1980. That’s seven consecutive cycles of contrasting results in years in which there wasn’t a GOP incumbent in the White House. This year, though, former President Donald Trump is looking to break that streak, and he might well succeed after handily winning the Iowa caucuses last week. As of Monday at 5 p.m. Eastern, Trump also led in 538’s New Hampshire polling average with about 51 percent, yet his 14-point advantage there was much smaller than his edge was in Iowa. This gives former U.N. Ambassador Nikki Haley, who was polling at about 37 percent, a small but not impossible shot at achieving an upset victory.
And the good news for Haley is that, over the past quarter century, victories by candidates who generally aligned with social conservatives in Iowa have been followed by wins by more mainline conservative, moderate or outsider candidates in New Hampshire, who appealed to a broader part of the primary electorate.
In 2000, then-Texas Gov. George W. Bush consolidated a large portion of the GOP with his message of “compassionate conservatism,” which helped him carry Iowa. However, then-Sen. John McCain’s “straight talk express” and maverick reputation helped him trounce Bush in New Hampshire, although Bush went on to win the nomination. In 2008, former Arkansas Gov. Mike Huckabee surged late and won Iowa on the back of white evangelical conservatives, while McCain again won New Hampshire en route to claiming the GOP nod.
In 2012, former Sen. Rick Santorum somewhat repeated Huckabee’s success to win Iowa (although it took more than two weeks to confirm that Santorum had won), but former Massachusetts Gov. Mitt Romney, the eventual nominee, captured New Hampshire with the backing of moderate and somewhat conservative primary voters. Then in 2016, Sen. Ted Cruz won Iowa with a message aimed at religious conservatives, while Trump captured New Hampshire thanks to a broader coalition of primary voters before going on to claim the Republican nomination.
One reason for these divergent results is that New Hampshire primary voters are less likely to identify as out-and-out Republicans than Iowa caucusgoers. Last week, 4 in 5 GOP caucusgoers identified as Republicans, according to the entrance poll, and at least 3 in 4 said the same in 2012 and 2016. By comparison, only about half of New Hampshire primary voters in 2012 identified as Republican, while slightly more than half did so in 2016. Conversely, at least 40 percent of the Granite State electorate considered itself independent in 2012 and 2016, compared with less than a quarter of voters in Iowa.
The different electoral rules for the presidential contests in each state help explain some of this contrast. In Iowa, only registered members of a party may participate in that party’s caucuses, and caucusgoers must attend these events at an appointed time on a weekday evening. By contrast, state-run primaries like New Hampshire’s generally give voters roughly 12 hours to visit their regular polling place to cast a ballot, and they usually include at least a limited option to vote absentee. As a result, caucuses have much lower turnout than primaries. On Monday, only about 5 percent of Iowa’s voting-eligible population — anyone eligible to register and vote — took part in the Republican caucuses, whereas we can expect at least 20 percent (if not more) of New Hampshire’s VEP to vote in the GOP primary (each party has cleared that mark in competitive primaries since 2004).
But New Hampshire may also have a somewhat more independent-minded electorate. Party registration and party identification are not the same thing, but among the 31 states that have party registration, New Hampshire has one of the largest percentages of registered voters who aren’t registered as either a Democrat or Republican. As of the end of 2023, 39 percent of New Hampshire voters were “undeclared” — that is, not registered with a party — while 31 percent were registered as Republicans and 30 percent as Democrats.
And unlike in Iowa’s caucuses and many other states’ primaries, New Hampshire permits these undeclared voters to participate in party primaries. Although those who aren’t registered with a party still often identify with or lean toward a party, allowing such voters to participate further broadens the electorate in New Hampshire. For instance, independents who lean left (but not registered Democrats, counter to the false claim Trump made last week) can participate in a GOP primary if they so choose — an especially potent possibility in years when a Democratic incumbent is in the White House and the Democratic primary is less interesting, as is mostly the case in 2024.
We’ve previously seen how New Hampshire’s less restrictive rules and a one-sided primary year can produce a less solidly Republican electorate. In 2012, then-President Barack Obama faced no notable opposition in the Democratic primary, so Republicans had the only real action. That year, the New Hampshire exit poll found that 53 percent of GOP primary voters were registered Republicans when they went to the polls, while 45 percent were undeclared voters (New Hampshire permits same-day registration on election day, and 2 percent said they hadn’t previously been registered). That marked the smallest share of New Hampshire’s GOP primary electorate registered with the party in any incumbent-less Republican primary dating back to 2000.
New Hampshire’s broader pool of primary voters also tends to be less ideologically conservative than Iowa caucusgoers. Last week, about half the Iowa Republican electorate identified as very conservative, and only 11 percent said they were moderate or liberal. But the share of very conservative New Hampshire primary voters didn’t cross the 30 percent mark in 2012 or 2016, with far more saying they were somewhat conservative. In 2012, a whopping 47 percent identified as moderate or liberal, and even though that figure dropped to 29 percent in 2016, it still was about double the share of caucusgoers who identified that way in Iowa that cycle.
Once again, electoral rules play a role in this contrast. In part because of their higher barriers to participation, caucuses tend to attract the most committed and ideologically minded members of a party; such voters make up a larger proportion of a much smaller caucus electorate. On the other hand, primary electorates are wider, especially when they can include independents, so we can expect New Hampshire’s primary electorate to be less conservative on Tuesday. In New Hampshire, winning over those who call themselves somewhat conservative tends to be key to a Republican primary victory. For instance, Trump led with 38 percent among that group in 2016, and Romney garnered an even larger 48 percent in 2012.
Another reason for these ideological differences is that New Hampshire’s population has a smaller share of white evangelical Christians — a core part of the GOP base — than Iowa does. This is notable because white evangelical Christians are among the Americans most likely to identify as Republican, and they are more conservative than non-evangelical Republicans. Overall, only 8 percent of Granite Staters identify as white evangelical Christians, according to the Public Religion Research Institute, below both the national average of 14 percent and Iowa’s 19 percent mark. As a result, the share of the New Hampshire Republican primary electorate that identifies as white evangelical Christian is among the smallest in the country. Whereas 55 percent of Iowa caucusgoers identified as white evangelical Christians last week, less than a quarter said the same in the 2012 and 2016 New Hampshire GOP primaries.
More broadly, New Hampshire is one of the least religious states in the country: In 2016, the Pew Research Center reported that only one-third of Granite Staters qualified as highly religious — putting it in a tie for last among the 50 states — based on an index of questions about religious views and activities from Pew’s Religious Landscape Study. By comparison, Iowa ranked 19th.
Like much of New England, New Hampshire also has a larger-than-average population share with at least a four-year college degree. Overall, 39 percent of Granite Staters 25 or older have at least a bachelor’s degree, compared with 34 percent nationally and 30 percent in Iowa, according to American Community Survey data. And the gap in Republican candidate preference between those with and without a four-year degree is already clear from the Iowa caucuses. According to entrance polls of Iowa, Haley won 28 percent of college graduates but only 9 percent of the rest of the electorate; by contrast, Trump won 37 percent of college grads but a whopping 67 percent of those without a degree. National polling data more broadly has shown similar splits.
However, while New Hampshire has a larger share of voters with a four-year degree, its Republican electorate won’t necessarily be notably more highly educated. In Iowa, around half of entrance poll respondents reported being college graduates last week, similar to 2016 GOP caucusgoers. And in New Hampshire, a slight majority of Republican primary voters said they were college grads in 2016. If it seems surprising that New Hampshire wouldn’t have a far more highly educated primary electorate given the state’s overall demographics, lower-turnout caucuses may once again play a role: Higher levels of education are associated with higher turnout among individual voters, so it follows that college-educated voters would have an especially outsized influence in a lower-turnout event.
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Ultimately, we can expect New Hampshire primary voters to be a less solidly Republican, less conservative and less religious group compared with the caucusgoers in fellow leadoff state Iowa. That reality has left open a slim possibility that Haley can pull off a long-shot upset over Trump, whereas a Trump victory in Iowa was never in doubt.
Still, many questions won’t be answered until we start getting results on Tuesday night. Just how many independents will participate? Will the lack of a highly contested Democratic race push many left-leaning independents to vote in the GOP race to oppose Trump? Will Trump garner support from a majority of self-identified Republicans like he did in Iowa, or will he have weaker backing in a less religious and conservative state? The answers to these queries will likely decide whether New Hampshire — and perhaps the GOP race as a whole — truly is competitive or if the Granite State will only increase the tailwinds for Trump as he sails to the Republican nomination.