There were a lot of moving parts tonight, so here's a quick summary all in one place:

- Trump is projected to finish first; he currently has 51 percent of the vote.
- DeSantis is projected to finish second; he currently has 21 percent.
- Haley is projected to finish third; she currently has 19 percent.
- Ramaswamy is projected to finish fourth; he is dropping out of the race.

—Nathaniel Rakich, 538

In her speech tonight, Haley linked Biden to Trump, reminding us that both are old (she said both are about 80 years old), and that most Americans don't want another Trump-Biden match up. But Republicans are much less likely than Democrats to admit their candidate is too old, so the audience within her party for that message is small.

—Meredith Conroy, 538 contributor

Johnson County, one of the most diverse, well-educated counties in Iowa, now shows Nikki Haley in the lead … by 1 vote, according to ABC News.

—Mary Radcliffe, 538

Our friends over at The 19th have pointed out that Haley is likely to become the first woman to win more than one delegate in the Republican primary. If she pulls off an upset in New Hampshire later this month, she'll become the first woman to win a Republican primary contest. In that same state, then-former Sen. Hillary Clinton was the first woman to ever win a major party primary contest in 2008, when she captured a surprise victory after coming in third in Iowa, which Obama won.

—Monica Potts, 538