In the years since the National Security Council was created, presidents have reorganized it to suit their own style of decision-making. President Lyndon Johnson set up a regular Tuesday working lunch that brought together the secretaries of state and defense, the CIA director and the chairman of the Joint Chiefs of Staff. Under President Richard Nixon, the NSC again expanded and focused on gathering analysis from departments for National Security Adviser Henry Kissinger, who then synthesized it into written recommendations for Nixon. In many ways, the national security adviser became more important than Secretary of State William Rogers, who sometimes wasn't even consulted about foreign policy decisions.
President Gerald Ford pretty much kept Nixon's system, while under President Jimmy Carter, the national security adviser turned into more of a public spokesman for the president's ideas, rather than a behind-the-scenes manager.
Under President Ronald Reagan, the NSC morphed from an advisory group into an organization that actually carried out secret operations to support foreign and national security policy — an overreach that led to the Iran-Contra scandal, which we'll talk about later. Reagan's successor, George H.W. Bush, went back to the NSC's original function. He created a flow chart full of committees whose goals were to come to agreements and coordinate policy across the Executive Branch. It worked smoothly enough that the next three Presidents — Bill Clinton, George W. Bush and Barack Obama — stuck to the senior Bush's approach [source: Whittaker, et al.].
However, by the Obama administration, the NSC had ballooned to about 400 staffers, four times the size it was in the Clinton administration. Half of them were on loan from various departments and agencies [source: DeYoung]. The sheer numbers led to internal complaints about the difficulty of making any decisions, with months, sometimes years of repetitive meetings.
President Donald Trump came into office in January 2017 promising to shake things up in Washington, and that included the NSC. About a week after taking office, he issued a memorandum that radically reorganized the council. Trump made White House political strategist Steve Bannon — a figure known for his controversial far-right views — a full-fledged member of the NSC.
At the same time, he excluded the chairman of the Joint Chiefs of Staff and the director of national intelligence, two officials included by law in the NSC, from the list of those who usually would attend NSC meetings, decreeing instead that they "shall attend where issues pertaining to their responsibilities and expertise are to be discussed" [sources: Jaffe, White House].
Although there was an uproar in the press on this last point, some say it was overblown. Under previous presidents the chairman of the Joint Chiefs and the director of national intelligence sometimes skipped meetings if the issue being discussed didn't pertain to them [source: Qiu].