There is a fear among some of Mr. Trump’s senior advisers about leaving him alone in meetings with foreign leaders out of concern he might speak out of turn. General McMaster, in particular, has tried to insert caveats or gentle corrections into conversations when he believes the president is straying off topic or onto boggy diplomatic ground.
This has, at times, chafed the president, according to two officials with knowledge of the situation. Mr. Trump, who still openly laments having to dismiss his first national security adviser, Michael T. Flynn, has groused that General McMaster talks too much in meetings, and the president has referred to him as “a pain,” according to one of the officials.
In private, three administration officials conceded that they could not publicly articulate their most compelling — and honest — defense of the president: that Mr. Trump, a hasty and indifferent reader of printed briefing materials, simply did not possess the interest or knowledge of the granular details of intelligence gathering to leak specific sources and methods of intelligence gathering that would do harm to United States allies.