With most ballots counted, Mr. Sanders had about 26 percent of the vote, fending off Mr. Buttigieg and another moderate rival, Amy Klobuchar. Elizabeth Warren and Joe Biden finished well behind.

The details: Here are five takeaways from Tuesday, as well as full results from the Democratic race and the Republican primary, which President Trump won easily.

News analysis: “Mr. Sanders’s early hold on a fractured primary field has laid bare a distressing truth for some Democrats: The man who has long resisted the party’s label might just become the standard-bearer.” Read more from our reporters in New Hampshire.

Related: Andrew Yang, the tech entrepreneur whose campaign was one of the Democratic primary’s most surprising story lines, dropped out. So did Senator Michael Bennet of Colorado.

Perspective: Opinion writers from The Times and elsewhere considered the prospect of Mr. Sanders as the Democratic nominee.