If for nothing else, Jodi Kantor’s The Obamas will be remembered for an anecdote from 2010. After he spent hours disputing an allegation in the French media that Michelle Obama thought life in the White House was “hell,” press secretary Robert Gibbs encountered senior adviser Valerie Jarrett. She told him the first lady was unhappy with his work. Gibbs exploded in a rage, informing Jarrett that she didn’t “know what the f— you’re talking about” and that if Mrs. Obama was displeased, well, “f— her too.” Subsequent relations between the senior adviser and press secretary were strained. Gibbs told Kantor...