WASHINGTON (Reuters) - In one of the most awkward moments of his time as U.S. secretary of state, Rex Tillerson realized his Mexican counterpart was in Washington only when he walked into a restaurant and found him dining with President Donald Trump’s son-in-law and senior adviser, Jared Kushner.

On another occasion, neither Tillerson nor Jim Mattis, who was then secretary of defence, knew Saudi Arabia and the United Arab Emirates planned to blockade their regional rival Qatar even though Kushner and another Trump adviser, Steve Bannon, had been told about it at a secret dinner with their governments.