The axis of adults refers to a group of early Trump administration political appointees who are often said to have acted as a bulwark against the president’s worst instincts. They are alternatively referred to by some as “the adults in the room.” Members of this informal group typically include Secretary of State Rex Tillerson, National Security Advisor H. R. McMaster, and Defense Secretary James Mattis. Upon Mattis’s defiant resignation announcement in December 2018, many observers marked the occasion as the death of the axis of adults. While Bolton’s ideological views diverge significantly from McMaster’s and Mattis’s, his desire to “save” Trump from making what he feels are dangerous decisions is perhaps the defining characteristic of the axis of adults.

The National Security Council (NSC) is a forum established in 1947 by President Harry S. Truman to oversee matters related to national security, the military, and foreign policy. It regularly convenes meetings of the Principals Committee to discuss more urgent matters of national security. Much of The Room Where It Happens takes place in these meetings, which are chaired by the national security advisor—in this case, Bolton. Regular attendees of Bolton’s Principals Committee include Secretary of State Pompeo, White House Chief of Staff Kelly, Defense Secretary Mattis, Treasury Secretary Mnuchin, and Chairman of the Joint Chiefs of Staff Dunford.