Donald Trump addresses the audience at a campaign rally in Nashua, N.H., on Jan. 29, 2016. (Reuters/Gretchen Ertl)

On Thursday evening, CNN and its partner WMUR released a new poll of the Republican field in New Hampshire, one of the first from a major firm in the race after Iowa -- and one that can be compared to a survey from right before the caucuses.

We'd noted another poll which seemed to indicate a big surge in support in the state for Marco Rubio, following his surprisingly strong finish in Iowa. The CNN/WMUR poll seems to confirm it, with Rubio jumping 7 points since right before Iowa. That's the same increase as in the University of Massachusetts-Lowell/7 News poll we noted earlier.

But notice two other things. First, that it seems as though some of Rubio's support may have come from Chris Christie, who sank 5 points since before Iowa.

Notice, too, that graph on the right, in which the pollsters asked voters if there was anyone they would not vote for under any circumstance. In that survey, there's a clear winner: Donald Trump. When the pollsters asked before Iowa, 31 percent of New Hampshire Republicans (and independents who plan to vote in the Republican primary) said they would never vote for Trump. Now that number is up 6 points, to 37 percent. In other words, two-thirds of New Hampshire voters either plan to vote for Trump or say they never, ever will.

That last point is important because a lot of voters haven't yet made up their minds.

Nearly 6 in 10 New Hampshire Republicans say they're not set on a candidate yet, with five days remaining until they vote.

For a very long time, this race looked like it was a walk for Donald Trump. He's still got a robust lead, but if Rubio keeps surging and people get more turned off by Trump, it could be a lot closer than we'd have expected. It could, once again, come down to who turns out to vote.

And that's not good news for Donald Trump.