When Iranian Foreign Minister Abbas Araghchi stated that Tehran had spent two decades studying US wars to build a system capable of continuing to fight even if the capital was bombed, he was describing more than resilience; he was outlining the core logic of Iran's defence doctrine.
At the centre of this doctrine is what Iranian military thinkers term 'decentralised mosaic defence' – a concept built on one fundamental assumption: that in any war with the United States or Israel, Iran may lose senior commanders, key facilities, communications networks, and even centralised control, but must still retain the capacity to keep fighting. This means the priority is not merely defending Tehran or protecting the supreme leadership, but preserving decision-making, maintaining combat unit operations, and preventing the conflict from ending with a single devastating strike. In essence, Iran's military was constructed not for a short war, but for a protracted one.
'Mosaic defence' is an Iranian military concept most closely associated with the Islamic Revolutionary Guard Corps (IRGC), particularly under former commander Mohammad Ali Jafari, who led the force from 2007 to 2019. The idea is to organise the state's defensive structure into multiple regional and semi-independent layers instead of concentrating power in a single command chain that could be paralysed by a decapitation strike. Under this model, the IRGC, the Basij militia, regular army units, missile forces, naval assets, and local command structures form parts of a distributed system. If one component is hit, others continue to function; if senior leaders are killed, the chain does not collapse; if communications are severed, local units retain the authority and capability to act autonomously.
The doctrine has two central aims: to make Iran's command system difficult to dismantle by force, and to render the battlefield itself harder to resolve quickly by transforming Iran into a layered arena of regular defence, irregular warfare, local mobilisation, and long-term attrition. This reflects a strategic shift shaped by regional shocks following the US invasions of Afghanistan in 2001 and Iraq in 2003. The rapid collapse of Saddam Hussein's regime reportedly left a deep imprint on Iranian strategic thinking, highlighting the vulnerabilities of a highly centralised state when confronted with overwhelming American military power.
In practice, the doctrine assigns distinct roles to different institutions. The regular army (Artesh) is expected to absorb the initial blow, with its armoured, mechanised, and infantry formations serving as the first line of defence to slow enemy advances. Air defence units employ concealment, deception, and dispersal to blunt enemy air superiority as much as possible. The IRGC and Basij then assume a deeper role in the subsequent conflict phase, tasked with turning the war into one of attrition through decentralised operations, ambushes, local resistance, disruption of supply lines, and flexible manoeuvres across varied terrain, including urban centres and remote regions.
Naval forces contribute through anti-access tactics in the Persian Gulf and around the Strait of Hormuz, aiming to make free movement hazardous and costly via fast attack craft, mines, anti-ship missiles, and the threat to one of the world's most critical energy corridors. Missile forces, especially those controlled by the IRGC, serve as both a deterrent and a deep-strike capability, intended to impose costs on enemy infrastructure and military targets. Iran's wider regional network of allied armed groups and partner forces across the Middle East further widens the battlefield, ensuring that any war with Iran does not remain confined to its territory.
One of the clearest expressions of this doctrine is economic as much as military. For instance, a Shahed drone is widely estimated to cost tens of thousands of dollars to produce, while intercepting it can incur vastly higher expenses when accounting for interceptor missiles and integrated defence systems. This asymmetry matters because it turns time into a strategic weapon: if one side can manufacture low-cost weapons in large quantities while forcing its opponent to spend far more on defence, prolonging the conflict itself becomes a means of pressure. The objective is not necessarily to achieve immediate battlefield superiority, but to make the cost of countering every threat unsustainable over time.
Iran's doctrine did not emerge in an intellectual vacuum; it overlaps significantly with the theory of prolonged war famously associated with Mao Zedong. During the Japanese invasion of China, Mao argued that a weaker side could survive initial imbalances, stretch the conflict, wear down the enemy's logistics and political will, and gradually alter the balance over time. While not a direct copy, Iran's approach shares the same central premise: that war is not decided solely by relative military capability at the outset, but is also shaped by endurance, adaptability, and the ability to withstand the opening shock.
Among the prominent ideological figures linked to this thinking is Hassan Abbasi, a hardline strategist often described as one of the IRGC's key theorists of asymmetric and long-duration conflict. His significance lies not only in military ideas but in how he connects strategic concepts to ideological narrative, framing prolonged war as a political and civilisational struggle where society, belief, and state institutions must all be prepared to absorb pressure and continue functioning. Mohammad Ali Jafari, meanwhile, helped institutionalise much of this thinking, embedding concepts like decentralised defence and localised command more deeply into the IRGC structure.
Perhaps the clearest manifestation of this wartime logic is in succession planning. Before his killing, Supreme Leader Ali Khamenei reportedly instructed senior Iranian officials to ensure multiple pre-designated successors existed for every key military and civilian post, with as many as four replacements for each senior position – giving rise to the notion of the 'fourth successor'. The aim was not merely to name an heir at the top, but to build layers of succession throughout the system so that the assassination, disappearance, or isolation of one leader would not cause paralysis. Concurrently, a narrow inner circle was reportedly authorised to make critical decisions if communication with top leadership became impossible, reflecting the same logic as mosaic defence: avoid dependence on any single node and enable state continuity after severe shock.
The United States and Israel have long relied on doctrines of rapid dominance, precision targeting, and leadership decapitation, expecting that destroying command centres, communications nodes, and senior figures would lead to systemic collapse or strategic paralysis. Iran's response has been to design against that outcome, acknowledging vulnerability but building on the assumption of severe loss and disruption, with continuity preserved through redundancy, decentralisation, and organisational resilience. This approach was shaped not only by foreign threats but by Iran's internal history, including post-1979 revolutionary challenges from armed opposition groups like the Mujahedin-e Khalq and the attritional lessons of the eight-year Iran-Iraq War.
Taken together, these elements point to a straightforward conclusion: Iran's strategy was not crafted for a brief exchange of blows, but for a war where commanders might be killed, communications severed, infrastructure hit, and central authority strained – yet where the state, armed forces, and broader security apparatus would continue to function. This is the essence of mosaic defence: it is not merely a military tactic, but a theory of survival. It assumes the enemy may dominate the skies, strike first, and strike hard, but also that war can be extended, dispersed, and made costly enough to frustrate the pursuit of quick victory. The 'fourth successor' puzzle fits into this broader Iranian view of conflict, where the system must absorb shock, replace itself under fire, and turn the passage of time into part of its defence – meaning that even the death of a central leader like Khamenei was something the doctrine was built to outlive.
Source: www.aljazeera.com