The heads of the United States Federal Executive Departments, known as secretaries of their respective department, form the traditional United States Cabinet, an executive organ that serves at the pleasure of the president and normally acts as an advisory body to the presidency.
Since 1792, by statutory specification, the United States Cabinet constituted a line of succession to the presidency, after the Speaker of the House and the president pro tempore of the United States Senate, in the event of a vacancy in both the presidency and the vice presidency. The Constitution refers to these officials when it authorizes the President, in Article II, section 2, to "require the Opinion, in writing, of the principal Officer in each of the executive Departments, upon any Subject relating to the Duties of their respective Offices." In brief, they and their organizations are the administrative arms of the President.