Earlier this week, Iran celebrated its National Army Day, and at least on the face of it nothing remarkable happened. As is customary, Iranian President Hassan Rouhani addressed a military parade showcasing the country's military strength. He claimed that under his leadership the parts of Iran's defence budget related to “resilience” had increased by 145 per cent. Iranian Supreme Leader Ayatollah Ali Khamenei also met with a group of army commanders and personnel and stressed the importance of raising their living standards. However, beyond the grandstanding and political promises an important statement by the commander of the Iranian army may have gone almost unnoticed. In an interview with the Iranian Fars News Agency, Brigadier-General Kiumars Heidari announced major structural changes to Iran's army encompassing everything from human resources to logistics to armaments in order to transform it into an “offensive” force. This was a major policy announcement with potentially far-reaching consequences for Iran's foreign policy and internal defence-related power dynamics. If implemented, Heidari's proposed modernisation policy would not only radically alter Iran's defence doctrine, but just as importantly would also reverse the army's subservient relationship to the country's Islamic Revolutionary Guard Corps (IRGC). The announcement is also particularly important because it heralds a radical transformation in Iran's defence doctrine. The existing doctrine is essentially defensive and is grounded in the experience of the long-running Iran-Iraq War in the 1980s. The timing of the announcement is important as it coincided with the 30th anniversary of Iran's ill-fated “Karbala” offensives in the final years of the Iran-Iraq War. Beginning in late 1986, Iran started a concerted campaign to capture Iraq's second city Basra with a view to forcing the regime led by former Iraqi president Saddam Hussein to capitulate. The campaign culminated in May 1987 with the Karbala-10 offensive. By and large, it was unsuccessful, and the Iranian forces failed to capture Basra. The Karbala-4 offensive, in particular, was an unmitigated disaster that cost the lives of well over 10,000 Iranian combatants. However, the subsequent Karbala-5 offensive, which lasted until mid-February 1987, brought Iranian troops within 10 km of Basra. The Karbala campaign of late 1986 and early 1987 represents a traumatic heritage for the Iranian military because it highlighted the relatively narrow limits of the country's ability to project its military power. While there were multiple mitigating factors, not the least of which was Iran's lack of access to modern weapons as a result of sanctions, the bottom line was that the Iranian military lacked the ability to adequately attack the enemy. Decades later and despite a profound understanding of this inescapable fact, Iranian military planners and strategists have not adequately addressed this issue. The undeclared challenge to remedying it is the disparity of power between Iran's conventional armed forces and the IRGC, also known as the “Pasdaran”. Iran is the only country in the world with two fully independent military systems, a by-product of the Iranian Revolution in 1979 and the enduring need it produced among Islamic Republic loyalists for an ideological military force (in the form of the Pasdaran) to adequately protect revolutionary values. The conventional military's subservient relationship to the IRGC was fully established towards the end of the Iran-Iraq War, when the latter spearheaded all major offensives and directed defensive strategies. Yet, in terms of conventional military doctrine and attendant strategic planning, the IRGC lacks the organisational and logistical capacity to enable Iran to compete with major regional and international armed forces. Despite the fanfare which surrounds it, the IRGC is a relatively small organisation, with fully professional fighting personnel numbering only around 50,000. While the Pasdaran's expeditionary Al-Quds Force has made a major impact in Iraq and Syria during the present conflicts, the bottom line is that the IRGC has neither the resources nor the skills required to conduct military operations of sufficient scale against formidable state adversaries. Unlike the IRGC, the Iranian army has the institutional maturity (it is 55 years older than the Pasdaran), legitimacy, organisational capacity and, crucially, prestige required to transform itself into a 21st-century military force. Heidari's announcement also comes in the wake of the army's increasing confidence, as was evidenced, for example, by its deployment of special forces in Syria. However, the challenges facing Heidari's five-pronged modernisation strategy, composed of structures and organisation, human resources, combat capability, strategic planning and military engineering, should not be under-estimated. The Iranian army is faced by the twin challenges of a relatively under-developed domestic arms-manufacturing industry and a raft of sanctions and other political problems restricting the country's access to the international arms market. These challenges come into sharp relief in military aviation, where the latest version of Iran's putative stealth fighter, the Qaher F-313, has not been seen in flight. While the latest prototype appears to be an improvement on the original unveiled in 2013, aviation experts are far from convinced of the aircraft's flying capability, let alone combat potential. In the absence of major national companies specialising in the manufacture of weapons systems – and an adequately developed scientific infrastructure networked through universities and technical colleges – Iran will struggle to produce advanced military systems that can meet 21st-century needs. Nevertheless, technological challenges can be partially mitigated by proper organisational reforms, which could include fully professionalising the army and abolishing the conscription system. In terms of defence doctrine, and assuming the policy position set out by Heidari is fully implemented, Iran is also likely to gradually abandon a defensive posture in favour of a more strident and muscular approach to regional crises. This would effectively mean a shift away from using proxies to direct military interventions elsewhere – a radical shift whose repercussions would fundamentally alter Iran's relationship with regional foes like Saudi Arabia and Israel as well as the United States military in the Arabian Gulf. The writer is an analyst of Iranian politics and director of the research group Dysart Consulting.