Nikki Haley is gunning for second place in the Iowa Republican caucuses. In New Hampshire polls, she’s gaining on Donald Trump. Vox’s Andrew Prokop and Republican strategist Scott Jennings explain Haley’s rise.

This episode was produced by Miles Bryan, edited by Matt Collette, fact-checked by Laura Bullard, engineered by David Herman, and hosted by Noel King.

Transcript at vox.com/todayexplained

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