Fourth branch of government
In the American political system, the fourth branch of government refers to a group that influences the three branches of governance defined in the American Constitution (legislative, judicial, and executive). Such groups can include the press (an analogy for the Fourth Estate), the people, and interest groups. U.S. independent administrative government agencies, while technically part of the executive branch (or, in a few cases, the legislative branch) of government, are sometimes referred to as being part of the fourth branch.
In some cases the term is pejorative because such a fourth branch has no official status. The term is also widely used as a picturesque phrase without derogatory intent. Where the use is intended to be pejorative, it can be a rhetorical shorthand to illustrate the user's belief in the illegitimacy of certain types of governmental authority with a concomitant skepticism towards the origin of such authority.
The press 
The concept of the media or press as a fourth branch stems from a belief that the news media's responsibility to inform the populace is essential to the healthy functioning of the democracy. The phrase "Fourth Estate" may be used to emphasize the independence of the press particularly when this is contrasted with the press as a "fourth branch".
The people 
Identifying the people as a fourth branch of government may be an attempt to imply that the principle of "government by the people" has been broken.
Interest groups 
In an article titled "The 'Fourth Branch' of Government", Alex Knott of the Center for Public Integrity asserted in 2005 that "special interests and the lobbyists they employ have reported spending, since 1998, a total of almost $13 billion to influence Congress, the White House and more than 200 federal agencies."
Administrative agencies 
The administrative agencies that are funded from public money may exercise powers granted by Congress. Without appropriate controls and oversight this practice may result in a bureaucracy (in the original literal sense). Some critics have argued that a central paradox at the heart of the American political system is democracy's reliance on the what the critics view as undemocratic bureaucratic institutions that characterize the administrative agencies of government. An argument made for calling administrative agencies a "fourth branch" of government is the fact that such agencies typically exercise all three constitutionally divided powers within a single bureaucratic body: That is, agencies legislate (a power vested solely in the legislature by the Constitution) through delegated rulemaking authority; investigate, execute, and enforce such rules (via the executive power these agencies are typically organized under); and apply, interpret, and enforce compliance with such rules (a power separately vested in the judicial branch). Additionally, non-executive, or "independent" administrative agencies are often called a fourth branch of government, as they create rules with the effect of law, yet may be comprised at least partially of private, non-governmental actors.
Other "fourth branches" 
- Federal Reserve (central bank of the United States)
- Office of the Independent Counsel (or its successor the U.S. Department of Justice Office of Special Counsel)
- Office of Personnel Management (The civil service)
- Freemasons (during the 19th century when Americans thought secret societies had immense power)
Popular culture 
- In The Simpsons episode "Sideshow Bob Roberts" (originally aired October 9, 1994), Springfield's leading conservative talk radio host, Birch Barlow (a parody of leading American conservative talk radio host Rush Limbaugh) welcomes listeners to his show by introducing himself as the "fourth branch of government" and the "51st state."
- In 2007, the short-lived ABC drama-thriller Traveler, the fourth branch existed as a secret society created by the Founding Fathers and composed of the oldest families in the United States, whose purpose is to implement checks and balances on the U.S. government to guide the true course of America.
- Rapper and political activist Immortal Technique has a track entitled the "4th branch," in which he applies the role of said branch to the media in a pejorative manner. He implies in this track (or pretty much explicitly states) that the US media of the time acts more like another part of the government instead of its own independent entity, and he gives some of his reasons for this belief on the track.
- "4th Branch" is also the name of a record label - 4th Branch Records, owned by DJ Prezzident, based in Columbia, Missouri.
- Peter Gelderloos, 'The Fourth Branch of Government: Corporate Media Complicity from Miami to Iraq', Eat The State Vol 8, #8 (December 17 2003). Retrieved 27 September 2006.
- Martin A. Lee and Norman Solomon. Unreliable Sources (New York, NY: Lyle Stuart, 1990) ISBN 0-8184-0521-X
- Alex Knott, 'The 'Fourth Branch' of Government', AlterNet (April 8 2005). Retrieved 27 September 2006.
- Kevin B. Smith and Michael J. Licari, Public Administrations: Power and Politics in the Fourth Branch of Government (Roxbury, February 2006) ISBN 1-933220-04-X
- See generally United States Constitution, Article I
- See generally United States Constitution, Article III