The mosaic defence strategy or decentralized mosaic defence is a military doctrine developed by the Islamic Revolutionary Guard Corps which incorporates a flexible and decentralized command structure with built in redundancies. Developed in 2005 to combat a U.S. attack or foreign-backed revolution, the mosaic defense strategy was first implemented during the 2026 Iran war.
The mosaic defence was developed in 2005 by the IRGC's Center for Strategy, then led by Mohammad Ali Jafari, and influenced by the thinking of Hassan Abbasi, as part of Iran's land warfare doctrine. It was intended to combat what the regime perceived as its main threats: a soft revolution with foreign support or a United States military attack. It was developed as a response to US military action in the region, in Afghanistan and particularly during the fall of Saddam Hussein during the Iraq War when a high level of centralization prevented effective coordination between different units who could not conduct even basic manoeuvres without Saddam's approval.
The mosaic defence focuses, through a restructuring of its command and control structure into 31 separate provincial commands, each operating as a separate and independent entity with its own arsenals and stockpiles, allowing commanders the freedom of action in pursuit of pre-defined objectives, similar to German Auftragstaktik doctrine. The strategy would allow Iran to take advantage of its strategic depth and mountainous geography to mount an insurgency against invading forces, as Iran's size and mountainous geography would leave an invading army's supply lines vulnerable to ambush by stay-behind cells formed by the IRGC and augmented with Basij personnel. The objective of this strategy is to extend the war into an asymmetric war of attrition <nowiki/>to bleed the economy of the attacking country as it assumes that an attacking force would have superior conventional military power and intelligence.
This system creates an extra load on opposition intelligence services and armed forces as it means that tracking and taking out a small central leadership would not collapse the whole regime, minimizing the impact of decapitation strikes, and a much larger number of lower level and regional leaders need to be tracked and removed. It also makes the fighting more unpredictable as each commander will react differently. This strategy also acts as a deterrent as its focus is to overcome the initial shock, with the implication that a conflict would not be over quickly; with Ali Larijani stating during the 2026 Iran war that Iran has prepared itself for a long war.
The strategy, combined with its Fourth Successor leadership model (a layered system to ensure there are as many as four replacements available to fill the role of senior figures killed during a conflict, with Reza Talaei-Nik confirming that each figure in the command structure has named successors three ranks down) has been central to Iran's strategy during the 2026 Iran war, with Abbas Araghchi claiming on March 1st that the mosaic defence incorporated lessons learned from two decades of US interventions and would allow Iran to choose when the war will end.
The use of the mosaic defence strategy became apparent from the first Iranian strikes of the conflict; with strikes against Oman being attributed by Araghchi to a mistake by autonomous units who could not be contacted. Experts such as Hamidreza Azizi have warned that the decentralized nature of the conflict increases the risk of such errors, triggering escalations.
Expert on Iranian armed forces at the Center for Naval Analyses Michael Connell has state that while it appears that Iran has been delegating command to lower levels allowing them to fire a small number of strikes, their capabilities have clearly been degraded significantly, and that while the low level commanders are able to operate independently, a lack of central organisation is not ideal and the different groups operate in a disjointed fashion. Heather Williams, former deputy national intelligence officer for Iran at the National Intelligence Council has said that the mosaic defence appears to be helping weather the decapitation strikes against military leadership and allowing Iran to launch retaliatory strikes.