Since the beginning of 2023, Republicans have spent nearly $78 million on advertising in New Hampshire, a sum that includes significant expenditures from candidates no longer in the race, such as Chris Christie and Tim Scott. As in Iowa, the top spender on TV in New Hampshire has been Stand for America, the Super PAC supporting Haley, which has run $23.5 million in advertising in the Granite State, according to AdImpact. No other candidate or group comes close to matching that number — the next-closest is Trump-supporting MAGA Inc., at $8.4 million. Haley herself has spent $5 million, while Trump has spent $7.4 million (candidates can buy ads on TV at a more favorable rate than outside groups).

You can see how big a priority New Hampshire has been for Haley and her allies, who began advertising in New Hampshire back in August. Just half of the pro-Haley spending in the state — $15.8 million of $31 million total between her campaign and supportive super PACs — has come within the last month of the race. Trump, meanwhile, is a relative newcomer to the airwaves. Of the $15.7 million in pro-Trump spending all cycle, almost all of it, $13.6 million, has come since Dec. 19, coinciding with Haley’s surge in the state’s polls.

A glance at TV spending also helps explain why DeSantis’s campaign floundered in New Hampshire, where the governor once polled as high as 25 percent but has fallen to less than 6 percent in the final 538 average before his exit from the race on Sunday. From an advertising perspective, DeSantis had effectively given up on the state in recent months. His Super PAC, the aptly named “Never Back Down,” spent $8 million in New Hampshire from April to November 2023, but hadn’t spent anything since.

—Jacob Rubashkin, Inside Elections

DeSantis was polling at only about 6 percent in New Hampshire when he dropped out of the race on Sunday, but 6 percent isn't nothing, and DeSantis's departure could help Trump on the margins tonight. According to an average of crosstabs from national primary polls, 48 percent of DeSantis supporters nationwide said that Trump was their second choice, while only 28 percent said Haley was. In New Hampshire, though, it was a little closer: 48 percent of DeSantis supporters there said Trump was their second choice, while 34 percent said Haley was.

If you take those numbers literally, we'd expect Trump to gain 3 points (48 percent of 6 percent) in New Hampshire from DeSantis's withdrawal, and Haley to gain 2 points (34 percent of 6 percent). However, DeSantis's endorsement of Trump on his way out of the race could mean Trump will gain even more ground. Overall, DeSantis's withdrawal is probably not good for Haley — although one New Hampshire poll, from Emerson College/WHDH-TV, did go against the grain and say that most DeSantis supporters would turn to Haley. These crosstabs all have very small sample sizes, and thus come with larger-than-usual margins of error, so we'll just have to see which of them is closest to the mark!

—Nathaniel Rakich, 538

In a January survey by Emerson College/WHDH-TV, just 52 percent of those who planned to vote in the New Hampshire Republican primary said they were registered as Republicans. Four percent said they were registered as Democrats, and 45 percent said they were registered as independents or with another party. (It’s worth noting that Democrats cannot vote in the Republican primary, so those 4 percent are going to be in for a disappointment when they show up to the polls.)

—Mary Radcliffe, 538

Although Iowa and New Hampshire both lead off the presidential nomination process and are both very white states, they have different-looking Republican electorates. Overall, New Hampshire GOP primary voters are less Republican, conservative and religious than Iowa Republican caucusgoers. This 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.

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. Differing electoral rules help explain some of this contrast, as caucuses have lower participation rates than primaries. 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. But critically, New Hampshire permits independent voters to participate in party primaries, unlike Iowa's caucuses and many other states' primaries.

New Hampshire Republican primary voters also tend to be less ideologically conservative than Iowa GOP caucusgoers. 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, whereas primaries attract a broader pool of voters, especially if independents are allowed to participate. Another reason for this ideological split 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.

—Geoffrey Skelley, 538

Coming into today, a big question was whether independents would turn out a high level and put Haley in a competitive position versus Trump. Based on the preliminary exit poll, the answer was yes — but not enough for Haley to win. Overall, 45 percent of voters identified as independent or something else, and they went for Haley by 24 points, 61 percent to 37 percent. However, self-identified Republicans made up 4 percent of the electorate and. broke for Trump by 39 points, 74 percent to 25 percent. Even with a little help from the 6 percent who identified as Democrats (went for Haley 84 percent to 6 percent), Haley couldn't catch Trump because of his overwhelming edge among Republicans.

Another aspect of the independent question is New Hampshire's electoral access rules, which permit those not registered with a party — "undeclared" voters — to vote in party primaries. That group, which includes many self-identified independents, did turn out in a big way, making up 47 percent of the electorate to registered Republicans' 50 percent (same-day registrants made up the rest). And Haley won among undeclared voters 66 percent to 32 percent. But Trump won among registered Republicans 74 percent to 24 percent. These numbers will change somewhat after further weighting based on the results, but the big takeaway is that independents put Haley in range, but Trump's dominance among Republicans preserved his edge.

—Geoffrey Skelley, 538