Mark Corallo, the spokesman, had grown frustrated with the operation and the warring factions and lawyers, these people said. Corallo also was concerned about whether he was being told the truth about various matters, one of these people said.

Corallo has been close to special counsel Robert Mueller, who is leading the Russia investigation, and has praised him publicly. He didn’t like the strategy to attack his credibility, one person who spoke to him said…

Corallo had told an associate that the dynamics in the White House were untenable and that there was “too much fighting all the time,” in the words of one person who spoke to him.