President Trump seemed poised to avoid a government shutdown and to carry his fight for a border wall into 2019, when the House will be controlled by Democrats. Then he shot down the spending deal. So what happened?

Also, to cap off a chaotic day of breaking news, Jim Mattis resigned as secretary of defense. Guest: Jonathan Weisman, the deputy Washington editor of The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.