A number of senior administration officials believe one catalyst for the problems was the sudden departure of staff secretary Rob Porter, who left the White House last month amid allegations of abuse by his two ex-wives.

Porter was part of an exodus of advisers who had worked to try to keep Trump focused and away from his protectionist instincts. They had prevented him from ripping apart trade agreements and imposing major tariffs on other countries, even U.S. allies such as Canada and Germany.

Porter tried to streamline decisions and corral divergent views into joint meetings, a challenge in a White House that has secret alliances and a flair for sensationalism. There was a weekly meeting on trade that included top advisers and was held to ensure there would not be surprises or rash decisions. Porter, these officials said, often presented the consensus views of the group or gave Trump recommendations. But Porter’s critics believed he was stonewalling and isolating people such as Navarro, whom Trump often wanted to hear from but did not have direct access to.