As you may have figured out already, the National Security Council has multiple layers. At the top, there's the principals committee, composed of some of the national security leaders in the U.S. government. That includes the chairman of the Joint Chiefs, the director of national intelligence, and the secretaries of state, defense and energy, whose participation in the NSC is specified by law. Other nonstatutory members usually include the president's national security adviser, the White House chief of staff, the attorney general and various other cabinet members [source: Qiu].
But meetings are only a part of what the organization does. Other members are experts on regions and countries, as well as specialists in topics ranging from cyber security to public health. Their job is to make sure the top level of the NSC has the right information to make decisions.
When a president makes state calls to foreign leaders, for example, it's customary for an NSC senior staffer who's an expert on that country to brief the president beforehand, giving him a prediction of what the other head of state might say and outlining key U.S. policy objectives. Then, during the call, the staffer generally will be close by, listening in on the call and scribbling notes to the president or answering questions that arise [source: Palmeri].
On at least one occasion in U.S. history, though, the NSC has gone beyond its job of giving advice and coordinating policy, and actually gotten involved in clandestine operations. As we'll discuss in the next section, that didn't turn out well.