Well before this week’s revelations about President Trump’s interactions with Defense Secretary Jim Mattis in Bob Woodward’s new book, officials inside the White House have been actively discussing who will replace Mattis at the Pentagon — whenever he might step down.

Of course, in light of Woodward’s reporting that Mattis told associates Trump “acted like — and had the understanding of — ‘a fifth- or sixth-grader,’ ” internal speculation about Mattis’s potential departure has intensified. (Mattis issued a statement Tuesday calling the book “fiction.”) Many officials inside the White House and around the administration had already expected that Mattis would leave his post sometime over the next few months, completing a respectably long two-year stint at the helm of the Defense Department.

“The speculation about who replaces Mattis is now more real than ever,” said a senior White House official who was not authorized to speak about internal matters. “The president has always respected him. But now he has every reason to wonder what Mattis is saying behind his back. The relationship has nowhere to go but down, fast.”