“You treat me like a baby! Am I like a baby to you? I sit there like a little baby and watch TV and you talk to me?”

— Donald Trump to Paul Manafort in “Devil’s Bargain,” by Joshua Green.

Why does Mr. Trump’s team treat him like a kid? He is the president of the United States and, as he says, “you’re not.” He lives in the White House, where he gets two scoops of ice cream instead of one for dessert. He is commander in chief, eating “the most beautiful piece of chocolate cake” with the Chinese president while he fires missiles at Syria. As he told the Russians, “people brief me on great intel every day,” with lots of pictures and “tweet-length sentences.” He has a “beautiful Twitter account.” Uh-oh!

Mr. Trump’s staff can’t control him, so they coddle him. They make sure he starts his day with a packet of good news about himself, compiled by Republicans who get up early to search for positive stories, headlines, tweets or, failing those, flattering photos. “Maybe it’s good for the country that the president is in a good mood in the morning,” one of the Republicans said.

Mr. Trump likes “unstructured time” to watch TV. His favorite station is Fox News Channel but he’ll watch any show where they talk about him. If they say something bad about him, he tweets. That makes everyone nervous. His staffers try to limit his screen time during the day and keep him from “calling old friends and then tweeting about it.” But then it’s off to bed with his phone, and “once he goes upstairs, there’s no managing him.” Uh-oh!