In the United States, the deep state is an alleged entity that coordinates efforts by government employees and others to influence state policy without regard for democratically elected leadership. It has often been dismissed by numerous journalists and academics as a conspiracy theory. The term, which was originally used to refer to sophisticated shadow governments in countries like Turkey and post-Soviet Russia, has also been used in American political science to refer to entrenched government institutions wielding power, without necessarily implying a conspiracy. The term has been used in numerous published titles about the U.S. government written by, for example, Marc Ambinder, David W. Brown, Peter Dale Scott and Mike Lofgren.
The term gained popularity in some circles during the 2016 U.S. presidential election in opposition to establishment Republican and Democratic candidates and has also been used in 2017 during the Trump administration, which argues that deep states want to delegitimize the Trump presidency.
Deep state was defined in 2014 by Mike Lofgren, a former Republican U.S. congressional aide, as "a hybrid association of elements of government and parts of top-level finance and industry that is effectively able to govern the United States without reference to the consent of the governed as expressed through the formal political process."
In The Concealment of the State, professor Jason Royce Lindsey argues that even without a conspiratorial agenda, the term deep state is useful for understanding aspects of the national security establishment in developed countries, with emphasis on the United States. Lindsey writes that the deep state draws power from the national security and intelligence communities, a realm where secrecy is a source of power. Alfred W. McCoy states that the increase in the power of the U.S. intelligence community since the September 11 attacks "has built a fourth branch of the U.S. government" that is "in many ways autonomous from the executive, and increasingly so."
In the political journal Foreign Affairs, Jon D. Michaels discusses Trump and the deep state, and argues that the concept's relevance is quite limited in the United States. He is of the opinion that it is a more useful perspective in the study of developing countries such as Egypt, Pakistan and Turkey, "where shadowy elites in the military and government ministries have been known to countermand or simply defy democratic directives," but that "it has little relevance to the United States, where governmental power structures are almost entirely transparent, egalitarian, and rule-bound." 
Recent popular usage of the term has led to its appropriation by Breitbart News and other conservative and right-wing news outlets, where supporters of the Trump Administration have used it to support a variety of conspiracy theories. It has been dismissed by authors for The New York Times and The Observer. University of Miami Professor Joseph Uscinski says, "The concept has always been very popular among conspiracy theorists, whether they call it a deep state or something else." 
The "deep state" has been associated with the "military–industrial complex" cited by President Dwight D. Eisenhower in his 1961 farewell address, in which he stated: "In the councils of government, we must guard against the acquisition of unwarranted influence, whether sought or unsought, by the military-industrial complex. The potential for the disastrous rise of misplaced power exists and will persist." Mike Lofgren has claimed the military-industrial complex is the private part of the deep state. However, Marc Ambinder says has suggested that a myth about the "deep state" is that it functions as one entity; rather, that parts of the "deep state" are "often at odds with one another."
President Barack Obama's alleged lack of success of his campaign promises relating to Afghanistan war and civil liberties has been attributed by Tufts University professor Michael J. Glennon to what he calls the "double government"; the defense and national security network. Mike Lofgren felt Obama was pushed into the Afghanistan "surge" in 2009.
Donald Trump supporters use the term to refer to their allegations that intelligence officers and executive branch officials guide policy through leaking or other internal means. According to a July 2017 report by the United States Senate Committee on Homeland Security and Governmental Affairs, "the Trump administration was being hit by national security leaks 'on a nearly daily basis' and at a far higher rate than its predecessors encountered".
Donald Trump and Steve Bannon, his former chief strategist, have both made allegations about a deep state which they believe is interfering with the president's agenda. Some Trump allies and right-wing media outlets have alleged that former president Barack Obama is coordinating a deep state resistance to Trump. While the belief in a deep state is popular among Trump, his supporters and the Trump administration, critics dismiss it as a mere conspiracy theory and argue that the leaks frustrating the Trump administration lack the organizational depth of deep states in other countries, and that use of the term in the U.S. could be used to justify suppressing dissent.
- Deep state in Turkey
- Politics in the United States
- Shadow government (conspiracy)
- State within a state
- Ambinder, Marc; Grady, D.B. (2013). Deep State: Inside the Government Secrecy Industry. Wiley. ISBN 978-1118146682.
- Michael J. Glennon (2014). "National Security and Double Government" (PDF). Harvard National Security Journal. 5.
- Jordan Michael Smith (October 19, 2014). "Vote all you want. The secret government won't change". The Boston Globe.
- Michael Hafford (2017-03-09). "Deep State: Inside Donald Trump's Paranoid Conspiracy Theory". Rolling Stone. Retrieved 2017-03-13.
- Oliver Willis (2017-03-09). "The Alex Jones influence: Trump's "deep state" fears come from his conspiracy theorist ally and adviser". Salon. Retrieved 2017-03-13.
- "'Deep State' is the latest US conspiracy theory you need to know about". New Zealand Herald. 2017-03-10. Retrieved 2017-03-13.
- The State: Past, Present, Future Bob Jessop, page 224, December 2015 John Wiley & Sons
- New Directions in Criminological Theory Steve Hall,Simon Winlow page 229
- Amanda Taub (February 16, 2017). "As Leaks Multiply, Fears of a 'Deep State' in America". The New York Times.
- "Essay: Anatomy of the Deep State". BillMoyers.com. 2014-02-21. Retrieved 2017-04-22.
- The State: Past, Present, Future Bob Jessop, page 224, December 2015 John Wiley & Sons
- [The Concealment of the State] Jason Royce Lindsey, 2013 pages 35–36
- Scahill, Jeremy (2017-07-22). "Donald Trump and the Coming Fall of the American Empire". The Intercept. Retrieved 2017-07-29.
- Michaels, Jon D. Trump and the "Deep State". Foreign Affairs. September/October 2017.
- Taub, Amanda; Fisher, Max (February 17, 2017). "As Leaks Multiply, Fears of a 'Deep State' in America". The New York Times. Retrieved February 17, 2017.
- Rebellion Brews in Washington—But American ‘Deep State’ Is Only a Myth, John R. Schindler, The Observer, 22 February 2017
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- Ambinder, Marc; Ambinder, Marc (2017-03-10). "Five myths about the deep state". The Washington Post. ISSN 0190-8286. Retrieved 2017-08-09.
- "Vote all you want. The secret government won't change. - The Boston Globe". BostonGlobe.com. 2014-10-18. Retrieved 2017-08-22.
- "Background Briefing with Ian Masters". FD Media. Retrieved 2017-08-22.
- Lofgren, Mike (2014-02-21). "Essay: Anatomy of the Deep State". BillMoyers.com. Retrieved 2017-08-23.
- Ishaan Tharoor (February 1, 2017). "Is Trump fighting the deep state or creating his own?". The Washington Post.
- Crowley, Michael (September–October 2017). "The Deep State Is Real". Politico Magazine. Retrieved 2017-09-05.
- Julie Hirschfeld Davis (March 6, 2017). "Rumblings of a 'Deep State' Undermining Trump? It Was Once a Foreign Concept". The New York Times.
- Phillip Rucker, Robert Costa, Ashley Parker (March 5, 2017). "Inside Trump's fury: The president rages at leaks, setbacks and accusations". The Washington Post.
- Winter, Jana; Groll, Elias (2017-08-10). "Here's the Memo That Blew Up the NSC". Foreign Policy. Retrieved 2017-08-15.
- David Weigel (March 7, 2017). "Trump and Republicans see a 'deep state' foe: Barack Obama". The Washington Post.
- Stanage, Niall (June 5, 2017). "THE MEMO: Is Trump a victim of the 'deep state'?". The Hill.
- David A. Graham (February 20, 2017). "Why it's dangerous to talk about a deep state". The Atlantic.