In 2020, the general election polls missed Trump's support in key states, and the election came down to the wire. So far in 2024, though, polls don't seem to be understating Trump support. We'll see if that continues to hold.

—Dan Hopkins, 538 contributor

Something I’ve been turning over in my mind is whether Trump is more similar to an incumbent president seeking his party’s renomination, or to a candidate pursuing the nod in an open field. Trump has already been nominated twice by the GOP, and, obviously, occupied the White House for four years, making him perhaps one of the best-known people in the world. In that sense, he has a lot of the advantages of an incumbent. And it’s worth noting that some of the other presidents who have pursued non-consecutive terms, like Grover Cleveland and Theodore Roosevelt, also used the tools at their disposal — especially their ability to communicate with the public — to try to dominate their parties.

It matters for how we think about the eventual result. If Haley finishes with a strong second, that’s the kind of result that’s pointed to real vulnerability with past incumbents in New Hampshire. As Dan Hopkins pointed out earlier, competition in New Hampshire foreshadowed Lyndon B. Johnson’s decision not to run for reelection in 1968. George H.W. Bush was “jarred” in 1992 by Pat Buchanan taking 40 percent of the New Hampshire vote. And Gerald Ford had a narrow win over Ronald Reagan in 1976 in the vote totals, previewing not only a tough general election, but also brewing divisions in the GOP ranks.

This has implications for Biden as well, who is projected to win New Hampshire, despite not officially being on the ballot.

—Julia Azari, 538 contributor

DeSantis and Haley were vying to be the last opponent standing to Trump, and with DeSantis suspending his campaign over the weekend, Haley got her wish. An interesting side-effect is that we now have more of an ideological race. In a November 2023 survey, I found that Republicans evaluated Trump and DeSantis as similarly conservative. Haley, however, they saw as more moderate. So with DeSantis's departure, we have a clearer ideological divide.

—Dan Hopkins, 538 contributor

Trump tonight did something no Republican presidential candidate has done since President Ford in 1976: win both Iowa and New Hampshire in a contested primary. As I've been saying for a while, Trump is effectively the incumbent in this process — much in the same way that Ford was an incumbent with an asterisk in 1976. (He was the sitting president, but nobody had voted for him for anything.)

—Jacob Rubashkin, Inside Elections

Haley has been on quite a tear in New Hampshire polls over the last two months. She stands at 36 percent in 538's final New Hampshire polling average, compared to 19 percent on Dec. 1, 2023. Just ahead of the Iowa caucuses, that surge had narrowed Trump's margin in the Granite State to a little over 10 percentage points, much lower than his average margin across the other states.

Since Iowa, however, Trump has also surged in New Hampshire, shooting up to 54 percent percent, his best number of the whole cycle in the state. He is now 18 points ahead of Haley. It's likely Trump gained some votes from Ramaswamy, who was ideologically closest to him and endorsed the former president on stage in Iowa after withdrawing following his poor performance there. It is also possible that Trump will get a last-minute bump from DeSantis's drop out and endorsement on Sunday that is not fully captured by the polls.

Haley hitting, say, 40 percent in New Hampshire would be a feat. Across the polls we've collected, no other candidate even came close to that mark in any state. With such a showing, Haley could, somewhat credibly, claim a moral victory heading into Nevada and South Carolina next month. But, of course, moral victories do not win nominations.

—G. Elliott Morris, 538