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Irregular and Hybrid Warfare

By Master Sgt. Jacob A. Kirk

1st Squadron, 73rd Cavalry Regiment, 2nd Brigade Combat Team, 82nd Airborne Division

July 24, 2023

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U.S. Army soldiers

History shows the U.S. dominates conventional warfare but struggles against irregular forces. Due to multiple conflicts with insurgent forces, the U.S. developed counterinsurgency (COIN) methodology and tactics. However, as American military power has grown, so has the capability of adversaries, who have developed blueprints to defeat our military using irregular and hybrid warfare.

Understanding the Threat

COIN is the "military, paramilitary, political, economic, psychological and civic actions taken by a government to defeat an insurgency" (Joint Chiefs of Staff, 2018, p. b-2). Every major American war in recent memory, except for the Gulf War, has either turned into COIN operations, an irregular conflict or had at least some aspects of irregular warfare. From the Philippines War in the early 1900s to the recent conflict in Afghanistan, insurgent forces have played significant roles. Most recently, U.S. forces have fought irregular insurgent forces such as the Taliban and Al-Qaeda in Afghanistan. Fighting irregular forces develops complicated and complex issues for conventional militaries conducting offensive, defensive or stability operations.

Another emerging threat is hybrid forces, or forces combining conventional and irregular tactics. Our adversaries are training on this method to defeat U.S. forces (DA, 2019a). Irregular or hybrid threats provide ill-defined challenges requiring adaptive, capable forces. Through leadership, preparation and the best-educated noncommissioned officer (NCO) corps on Earth, the U.S. Army is ready to meet these challenges.


How do lessons learned in irregular warfare remain relevant despite long gaps between conflicts and perceptions that near-peer forces pose larger threats than reality dictates? NCOs and training. The NCO’s job is to record relevant tactics for the next generation of U.S. forces. Leaders ensure units conduct challenging and realistic training according to doctrine. For example, although the U.S. lost the Vietnam War, the NCO corps should have kept and trained on the lessons learned to prepare for the next irregular challenge. Leaders must ensure training encompasses all possibilities and tactics seen in irregular warfare, or U.S. forces will likely relive past mistakes.

SEAC Ramón Colón-López

Experienced NCOs can interject many firsthand experiences during training, amplifying standard training doctrine. Using proven and effective techniques simulates managing unforeseen battlefield circumstances and helps U.S. forces train broadly to defeat the most imminent threat. Predicting and understanding the future battlefield ensures all echelons achieve broad spectrums of training value regardless of the service component.

Numerous field manuals, guides, instructional pamphlets and regulations have been refined for the joint force to retain lessons learned from previous conflicts and develop training and doctrine to address it. The Center of Army Lessons Learned (CALL) website houses a wealth of knowledge on current lessons learned that NCOs could glean best practices from to counter rapidly emerging 21st century regular, irregular and hybrid threats.

Irregular Forces

From the end of the Cold War through the first Gulf War, U.S. forces were prepared and equipped to confront near-peer enemies like Russia. During the Afghanistan and Iraq wars, U.S. forces quickly destroyed both countries’ conventional forces, displaying their dominance and ability to conduct operations across land, sea and air. However, after transitioning to stability operations, they needed to prepare to fight hostile insurgents that deliberately blended in with civilian populations. Transitioning from large-scale ground combat to fighting an irregular force proved incredibly difficult.

Many lessons learned from earlier wars weren’t relevant in the 21st century. Iraq’s rebuilding allowed terrorist groups and insurgents to conduct hit-and-run attacks on U.S. forces. In Afghanistan, the Taliban retreated to mountains and neighboring countries where they could stage sporadic attacks, waiting out U.S. forces while discrediting our reasons for being there. U.S. forces recaptured COIN tactics, techniques and procedures to standardize the joint force's response to irregular threats.

After more than two decades of fighting irregular forces, the U.S. revised its doctrine. It is improving and transforming how U.S. and allied conventional forces fight irregular, conventional or hybrid threats. However, adversaries have analyzed and studied this adaptation and developed relevant hybrid warfare styles to combat our distinct conventional military advantage.

Hybrid Threat

The 149th Military Intelligence Group

The Geneva Convention and the Defense Department Law of War Manual outline standard warfare and force employment rules. These documents define hybrid threats as regular forces that disregard standard rules of warfare and employ irregular forces across battlefield domains. Hybrid threats use the best of traditional and irregular tactics and are the way of the future. As proved in 2001 and 2003, full-force conflict puts nations at a disadvantage against the U.S. military. Knowing that the U.S. will not leave countries in ruins with unnecessary collateral damage allows nations to oppose the U.S. The likelihood of near-peer threats opposing U.S. interests somewhere in the world is highly likely. Adversaries funding small irregular forces into conflict with conventional American forces and interests is an enemy strategy that needs to be anticipated and trained for.

In the digital age, everybody can and will see the actions and disposition of friendly and enemy forces. For the past 20 years, the U.S. has developed significant technology and advanced tactics, and the world watched as it either worked or failed. These observations allow adversaries to train and prepare to counter U.S. and allied advancements. Our most significant global threats, China and Russia, have undoubtedly prepared to use irregular and hybrid tactics already proven effective against U.S. forces thanks to around-the-clock world media coverage. Considering Russia and China are the two biggest military threats to the U.S., despite spending a fraction of America’s budget on their militaries, is paradoxical.


The simple fact is that the U.S. government has dedicated more than 500 billion dollars to our military every year for the last 20 years. This is more than the next ten biggest military budgets combined. Yet, we still consider Russia and China near-pear threats; this is a paradox (Duffin, 2021). The ultimate equalizer uses irregular warfare on nations reluctant to cause collateral damage. The U.S. has the best trained and equipped military in the world; however, enemies can minimize that training and technological advantage by effectively using irregular and hybrid warfare.

The Way Forward

Leaders at all levels are responsible for preparing the military to fight in conventional or irregular battles. Our adversaries know our strengths and weaknesses and will exploit them. Training needs to target unfamiliar areas that conventional forces historically struggle with to prepare them for future unconventional fights.

Identifying the U.S.'s strengths and weaknesses is complicated. As recently demonstrated in Afghanistan, ground-based elements need help identifying and engaging irregular non-state actors. Leaders at all levels should leverage their experience with irregular combat and implement those experiences into training events. The U.S. cannot afford to turn its Army into a force limited to defeating only conventional enemy forces. U.S. forces must identify key principles that can impact and enhance our combat power to sustain fighting forces that will remain relevant for years.


Predicting when, where or even how future conflicts will play out is an ill-structured problem for the military. With many variables and outside influences, the best U.S. forces can do is be adaptable to fighting environments. The Department of the Army (DA, 2019b) outlines adaptable leaders as being "comfortable with ambiguity. They are flexible and innovative—ready to face the challenges with available resources" (p. 8-3). The Army is training NCOs to work independently and make intelligent decisions in the face of adversity. Soldiers must remain agile and flexible in today's uncertain environment and keep lines of communication open. The U.S. military must learn from mistakes, share successes and display humility. Irregular warfare will require small unit leaders to make critical on-the-spot decisions that may impact organizational or strategic objectives. Commanders must trust their subordinate leaders to make and execute decisions based on the commander's intent. This trust is developed through extensive training experiences with the sole goal of generating mutual trust. Through this training process, leaders demonstrate competence and shared understanding, allowing commanders to accept risk and allow smaller units to operate independently with little oversight (DA, 2019c).


As U.S. military power has grown our adversaries have developed a blueprint to defeat that power through irregular and hybrid warfare. As repeatedly proven over the previous 20 years, U.S. forces struggle when fighting irregular threats. Historical lessons learned from more than two decades of war have influenced and led to the emergence of new doctrine. It is incumbent upon all leaders to maintain an ability to create realistic regular and irregular training scenarios to help keep the U.S. military ready to fight threats in any domain. The emerging threats are more plentiful than ever before because of advancing technologies. The U.S. must continue developing and refining ways to fight and win wars in increasingly complex and ill-structured operating environments.


Department of the Army. (2019a). Offense and defense. (ADP 3-90).

Department of the Army. (2019b). Army leadership and the profession. (ADP 6-22).

Department of the Army. (2019c). Mission command: Command and control of Army forces. (ADP 6-0).

Duffin, E. (2021). U.S. military spending from 2000 to 2020.

Joint Chiefs of Staff. (2018). Counterinsurgency. (JP 3-24).


Master Sgt. Jacob Kirk is the current Operations Sergeant Major for 1st Squadron, 73rd Cavalry Regiment, 2nd Brigade Combat Team, 82nd Airborne Division. He has served in various leadership assignments over the past 20 years ranging from Team Leader to Operations Sergeant Major. Kirk is a graduate of Class 72 Sergeants Major Course and holds a Bachelors in Workforce leadership and development.

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