The IRREGULAR WARFARE problem is defined in this joint operating concept as follows:
Adaptive adversaries such as terrorists, INSURGENTS, and criminal networks as well as states will increasingly resort to
irregular forms of warfare as effective ways to challenge conventional military powers. Advances in technology and other trends in the
environment will render such irregular threats ever more lethal, capable of producing widespread chaos, and otherwise difficult to counter. These threats are enmeshed in the population and increasingly empowered by astute use of communications, cyberspace, and technology, such that their impact extends regionally and globally. Many of these conflicts are essentially contests for influence and legitimacy over relevant populations.
https://www.jcs.mil/Portals/36/Documents/Doctrine/concepts/joc_iw_v2.pdf?ver=2017-12-28-162021-510