The president told one of his associates on Thursday night: “Stop calling John [Kelly] for anything. Call Nick. He’s my guy,” a person familiar with the conversation said…

Mr. Ayers’s ambition and advocacy for Mr. Pence’s interests have made him a polarizing figure within the West Wing, and could accelerate the departure of other White House officials, according to people familiar with the matter.

Secretary of State Mike Pompeo has been among the administration officials critical of Mr. Ayers, questioning his foreign-policy abilities, according to people familiar with the matter. The State Department didn’t immediately respond to a request for comment.