DOUGLAS GINSBURG, Federal Judge, U.S. Court of Appeals, D.C. Circuit:
The president’s cabinet comprises the vice president, the heads of the executive departments, and several other officials, including the white house chief of staff and the director of the Central Intelligence Agency.

The cabinet began with the heads of these four departments: the Secretary of State, the Secretary of the Treasury, the Secretary of War (later Defense), and the Attorney General.
As the nation grew, so did the executive branch – and hence the cabinet. The Departments of the Interior and of Agriculture were added in the 19th century as Americans moved west.
As America industrialized, Commerce and Labor was added in the early 20th century, and later split into two departments. Then came more departments: Health and Human Services, Housing and Urban Development, Transportation, Energy, Education, and Veterans Affairs. Homeland Security is the newest department – created after the terrorist attacks of 9/11.
The cabinet is so large, it has its own room with a big table in the West Wing of the White House. The growth of the cabinet reflects the growth of the government. A host of federal departments and agencies now cover areas once left entirely to the states – education, for example – something the Framers of the Constitution never dreamed of.