Irregular warfare (IW) is defined in United States joint doctrine as "a violent struggle among state and non-state actors for legitimacy and influence over the relevant populations." Concepts associated with irregular warfare are older than the term itself.
One of the earliest known uses of the term irregular warfare is in the 1986 English edition of "Modern Irregular Warfare in Defense Policy and as a Military Phenomenon" by former Nazi officer Friedrich August Freiherr von der Heydte. The original 1972 German edition of the book is titled "Der Moderne Kleinkrieg als Wehrpolitisches und Militarisches Phänomen". The German word "Kleinkrieg" is literally translated as "Small War". The word "Irregular", used in the title of the English translation of the book, seems to be a reference to non "regular armed forces" as per the Third Geneva Convention.
Another early use of the term is in a 1996 Central Intelligence Agency document by Jeffrey B. White. Major military doctrine developments related to IW were done between 2004 and 2007 as a result of the September 11 attacks on the United States. A key proponent of IW within US DoD is Michael G. Vickers, a former paramilitary officer in the CIA. The CIA's Special Activities Division (SAD) is the premiere unit for unconventional warfare , both for creating and for combating irregular warfare units. For example, SAD paramilitary officers created and led successful irregular units from the Hmong tribe during the war in Laos in the 1960s from the Northern Alliance against the Taliban during the war in Afghanistan in 2001 and from the Kurdish Peshmerga against Ansar al-Islam and the forces of Saddam Hussein during the war in Iraq in 2003.
Former CIA Paramilitary Operations Officer and Deputy Secretary of Defense Mick Mulroy said at an October 2019 workshop at RAND that the Irregular Warfare Annex is a critical component of the 2018 National Defense Strategy. He said irregular warfare included counter-insurgency, counter-terrorism, unconventional warfare, foreign internal defense, sabotage and subversion, as well as stabilization and information operations. It had traditionally been perceived as a predominately counterterrorism (CT) effort used to fight violent extremist organizations but it should be applied to all areas of military competition and against global powers competitors like China and Russia as well as rogue states like North Korea and Iran. Mulroy said that the U.S. must be prepared to respond with "aggressive, dynamic, and unorthodox approaches to IW," to be competitive.
Irregular warfare favors indirect warfare and asymmetric warfare approaches, though it may employ the full range of military and other capabilities, in order to erode the adversary's power, influence, and will. It is inherently a protracted struggle that will test the resolve of a state and its strategic partners. The distinction between regular and irregular forces is unrelated to the term "irregular warfare". The term, irregular warfare, was settled upon in distinction from "traditional warfare" and "unconventional warfare", and to differentiate it as such.
In an entry to the electronic open access Handbook of Military Sciences the Dutch military scholar Martijn Kitzen explores Operations in Irregular Warfare and the underlying body of knowledge which characterizes these conflicts as violent struggles involving non-state actors and states that seek to establish power, control, and legitimacy over relevant populations. In the chapter Kitzen provides an overview of much of the academic literature that covers this field.
- IW is a form of warfare that has as its objective the credibility and/or legitimacy of the relevant political authority with the goal of undermining or supporting that authority. IW favors indirect approaches, though it may employ the full range of military and other capabilities to seek asymmetric approaches, in order to erode an adversary's power, influence, and will.
- IW is defined as a violent struggle among state and non-state actors for legitimacy and influence over the relevant population(s)
- IW involves conflicts in which enemy combatants are not regular military forces of nation-states.
- IW is "war among the people" as opposed to "industrial war" (i.e. regular war).
Nearly all modern wars include at least some element of irregular warfare. Since the time of Napoleon, approximately 80% of conflict has been irregular in nature.
However, the following conflicts may be considered to have exemplified by irregular warfare:
Activities and types of conflict included in IW are:
According to the DoD, there are five core activities of IW:
Modeling and simulation
As a result of DoD Directive 3000.07, United States armed forces are studying irregular warfare concepts using modeling and simulation.
Wargames and exercises
There have been several military wargames and military exercises associated with IW, including:
- Unified Action 
- Unified Quest 
- January 2010 Tri-Service Maritime Workshop,
- Joint Irregular Warrior Series war games,
- Expeditionary Warrior war game series, and
- a December 2011 Naval War College Maritime Stability Operations Game focused specifically on stability operations in the maritime domain conducted by the Naval Service.
- ^ According to the definition of "regular forces", which came much after the American Revolutionary War (ARW), the American forces did not meet the following criteria at all times during the ARW:
- having a fixed distinctive emblem recognizable at a distance
- carrying arms openly
- conducting operations in accordance with the laws and customs of war
Notwithstanding, in terms of modern international humanitarian law which was also developed much later than the ARW, the American forces formed part of the armed forces of a party to an armed conflict but not belonging to that party's regular forces (since the United States of America did not exist and hence could not have had regular forces; the American forces were an insurgency at least until 1776) and operating in or outside of their own territory even if the territory is under occupation.
American forces did become regular forces but cannot be considered regular forces during the entire period of the ARW. For example, the American flag got established (1777) 2 years after the ARW started (1775). Also, there were great disparities between the American and British forces. It was not until France started to assist American forces (1778) that the disparity started to be narrowed. Conflict during the disparity surely counts as Asymmetric warfare. Also, the Boston Tea Party (1773) can be viewed as guerrilla tactics. At the very least, a good portion of the ARW should be counted as IW although the entire ARW being counted as IW is controversial. However, since more than 1/2 of the ARW was fought as ARW then it is thought that it is safe to classify it as IW even though that the American forces acted in all respects as regular forces towards the end of the conflict.
- ^ The Irregular Warrior, 4 October 2015
- ^ a b Gates, John M., "The U.S. Army and Irregular Warfare", The College of Wooster "Archived copy". Archived from the original on 2009-06-23. Retrieved 2010-02-20.CS1 maint: archived copy as title (link)
- ^ Moses, A. Dirk, "German intellectuals and the Nazi past," ISBN 978-0-521-86495-4, 2007 
- ^ a b White, Jeffrey B., "A Different Kind of Threat, Some Thoughts on Irregular Warfare", CIA, 1996 
- ^ "The National Military Strategy of the United States of America", United States Department of Defense, 2004 
- ^ Miller, LTC Frank A., "Irregular Warfare – Perhaps Not So "Irregular"", U.S. Army War College, 15 March 2006 
- ^ "The National Security Strategy of the United States of America", National Security Council, 2002 
- ^ Grant, Greg, "The Man Behind Irregular Warfare Push: Mike Vickers", DoD BUZZ, 7 April 2009 
- ^ Southworth, Samuel A., Tanner, Stephen, U.S. Special Forces: A Guide to America's Special Operations Units: the World's Most Elite Fighting Force, Da Capo Press, ISBN 0-306-81165-0, 2002
- ^ "Waller, Douglas, "The CIA Secret Army", Time Inc., 3 February 2003". time.com.
- ^ Stone, Kathryn & Williams, Anthony R., All Necessary Means: Employing CIA operatives in a Warfighting Role Alongside Special Operations Forces, United States Army War College (USAWC), 7 April 2003
- ^ Shooting at the Moon: The Story of America's Clandestine War in Laos, Steerforth Press, ISBN 978-1-883642-36-5, 1996
- ^ Woodward, Bob, Bush at War, Simon and Schuster, ISBN 0-7432-0473-5, 19 November 2002
- ^ Tucker, Mike & Faddis, Charles, Operation Hotel California: The Clandestine War inside Iraq, The Lyons Press, ISBN 978-1-59921-366-8, 2008
- ^ Woodward, Bob, Plan of Attack, Simon and Schuster, ISBN 978-0-7432-5547-9, 2004
- ^ https://www.rand.org/nsrd/news/2019/10/dasd-mulroy.html
- ^ "Irregular Warfare (IW) Joint Operating Concept (JOC)", Version 1.0, United States Department of Defense, 27 February 2009 
- ^ "US Irregular Warfare (IW) Analysis Workshop", Military Operations Research Society (MORS), 11 September 2007  Archived 2008-09-03 at the Wayback Machine
- ^ a b "Irregular Warfare (IW)", DoD Directive 3000.07, United States Department of Defense, 1 December 2008 
- ^ "Quadrennial Roles & Missions (QRM) Review Report", United States Department of Defense, January 2009 
- ^ "Irregular Warfare", Doctrine Document 2-3, United States Air Force, 1 August 2007 
- ^ Sookermany A. (ed) (2020) Handbook of Military Sciences. Springer, Cham doi:10.1007/978-3-030-02866-4
- ^ Kitzen M. (2020) Operations in Irregular Warfare. In: Sookermany A. (eds) Handbook of Military Sciences. p. 1-21. Springer, Cham doi:10.1007/978-3-030-02866-4_81-1
- ^ "Irregular Warfare Special Study", United States Joint Forces Command Joint Warfighting Center, 4 August 2006 
- ^ "Quadrennial Defense Review Report", United States Department of Defense, 6 February 2006 
- ^ Benest, David, "British Leaders and Irregular Warfare," 29 August 2007
- ^ a b The Imperitive: Irregular Warfare and the Future of Security, The Irregular Warrior, 
- ^ Marston, Daniel (2002). The American Revolution 1774-1783. Osprey Publishing. ISBN 978-1-84176-343-9.
- ^ The Core Activities of Irregular Warfare, The Irregular Warrior
- ^ "U. S. Army Enhancement of Irregular Warfare Modeling & Simulation", United States Army Modeling and Simulation Office, 24 February 2009 
- ^ "MORS Workshop Irregular Warfare (IW) II Analysis Workshop", Military Operations Research Society, 3–6 February 2009 
- ^ Cragg, Lt. Jennifer, "Behavior Studies May Improve Irregular Warfare Techniques", American Forces Press Service, 20 April 2009 
- ^ http://www.citmo.net/library/Military%20Support%20to%20Unified%20Action%20-%20ROL%20Focus%20for%20Policing%20WS.ppt
- ^ https://unifiedquest.army.mil/
- ^ a b c d "Maritime Stability Operations - PDF". docplayer.net. Retrieved 2017-09-07.