How Iran has changed its military strategy since the 12-Day War. Can the Islamic Republic survive US and Israeli attacks?

The Middle East is going through one of the most volatile moments in recent decades, after the confirmation of the killing of Iran's Supreme Leader, Ayatollah Ali Khamenei, following coordinated American-Israeli strikes. Tehran's swift and sweeping response indicates not just a desire for revenge, but also a strategic recalibration focused on regime survival, an Al Jazeera analysis says.

As the conflict escalates, analysts warn that the conflict could turn into a prolonged cycle of calibrated aggression rather than a decisive military confrontation.

Immediate retaliation and escalation signals

The Islamic Revolutionary Guard Corps (IRGC) responded to Khamenei's death with what it described as “the most powerful offensive operations in the history of the Islamic Republic's armed forces” against Israel and US military assets in the Gulf.

Tehran has launched waves of ballistic missiles and Shahed drones at Israel, US bases and infrastructure in the Gulf states. Although most of the projectiles were intercepted by Israeli, US and Gulf defense systems, some caused casualties and property damage. Civilian areas were affected by both direct hits and debris from interceptions.

Major incidents included attacks on the United Arab Emirates, including near iconic landmarks in Dubai, as well as strikes affecting airports in Abu Dhabi, Dubai and Kuwait. In Israel, the city of Beit Shemesh registered casualties following the impact of rockets.

The scale of the reprisals suggests a change in strategy, beyond the symbolic responses of the past.

Iran's Military Structure: Designed for Survival

Iran's response is anchored in a military architecture deliberately built for redundancy and regime protection.

The country operates two parallel military structures:

– Artesh, the regular army, responsible for territorial defense and conventional warfare.

– The Islamic Revolution Guards Corps (IRGC), which has the role of protecting both the national security and the political structure of the Islamic Republic.

Both answer directly to the Supreme Leader, the supreme commander of the armed forces.

The complex structure, supported by multiple intelligence services, is designed to prevent both external interference and internal threats such as coups. The IRGC's control over its missile and drone programs is the backbone of Iran's deterrence strategy.

Doctrinal change after the 2025 war

The current conflict cannot be separated from the June 2025 12-day war between Iran and Israel, in which the United States directly intervened with strikes on Iranian nuclear facilities.

This conflict marked a turning point, moving from indirect confrontations through intermediaries to high-intensity direct exchanges. Although Iran was able to cause some breaches in Israeli defense systems, its nuclear and military infrastructure suffered considerable damage.

According to analysis by John Phillips, a British safety, security and risk consultant and former chief military instructor, Tehran has adjusted its military doctrine from a defensive strategy to an asymmetric offensive posture, including:

Strengthening and dispersing “missile cities” to maintain the ability to fight back;

Using massive volleys of missiles and drones to overwhelm defense systems;

Activating regional allies to expand the theater of confrontation;

The threat of blocking the Strait of Hormuz as a tool of global economic pressure.

Strait of Hormuz: strategic economic lever

About 20–30% of global oil and gas supplies transit the Strait of Hormuz. Although Iran has not officially closed the sea route, the mere threat has caused concern in energy markets, and several oil tankers have avoided transit.

This economic dimension extends the conflict beyond the military plane, increasing international pressure to limit escalation.

Is Iran's strategy working?

From a deterrence perspective, Iran has demonstrated that it can maintain its ability to launch significant attacks despite the damage it has suffered previously. However, the vulnerabilities remain obvious:

Nuclear and missile infrastructure was affected.

The economy is weakened by sanctions and conflict.

Khamenei's death creates domestic political uncertainty.

The current strategy appears to be one of “calibrated escalation,” alternating between demonstration strikes and tactical pauses, to avoid an all-out conflict that could threaten the very existence of the regime.

Iran has a strong military, but currently has no ground troops, and the war is being waged in the air. Iran is at a disadvantage in air defense compared to the US and Israel. Tehran has increased its stockpile of air-to-air missiles, but only time will tell if it will be able to hold its ground,” said a military expert and former official.

Phillips compared Iran to a “wounded animal” and said that, strictly in terms of deterrence, Tehran's military strategy is working to the extent that it has shown it can still launch significant missile and drone strikes after the bombings in 2025. It has also forced Israel and the US to engage in a “sustained defensive and offensive campaign that requires intensive resources rather than a clean, one-off disarmament,” he added.

“However, Iran's nuclear and missile infrastructure was severely damaged, the economy weakened further, and Ayatollah Khamenei died in the attack on Tehran, which made the regime more vulnerable and tense domestically, an indication that the strategy succeeded in averting serious strategic setbacks,” he said.

How long can the conflict last?

Militarily, Iran can sustain years of intermittent missile, drone and cyber attack operations due to the relatively low cost of these systems, Philips explained.

But politically and economically, a prolonged conflict risks triggering severe recession, internal discontent and the erosion of the regime's legitimacy.

On the other hand, the United States and Israel have clear military superiority and can sustain extensive operations. However, their limits are rather political: domestic opposition, economic costs and international pressures.

“So Tehran has strong reasons to oscillate between escalation and tacit pauses rather than sustaining a full-scale ongoing war,” Phillips added.

Washington appears to be pursuing a strategy of controlled deterrence, avoiding an indefinite regional war.

On March 1, US President Donald Trump told the New York Times that the war could last four to five weeks. He told ABC News that after killing Khamenei, the US has no plans to target anyone else. He also told The Atlantic magazine that Iran's new leadership has agreed to talk with him, signaling a possible end to the current conflict.

Christopher Featherstone, an associate lecturer at York University's politics department, said that for the US and Israel, international condemnation and domestic opposition could be a limiting factor.

“The US can continue to deploy forces in the region, but any escalation of attacks would require a huge political effort and significant resources. Trump ran on a promise to be a president 'at home', but is increasingly aggressive abroad.” However, he remains cautious about sustained foreign engagement,” Featherstone told Al Jazeera.

A conflict without a clear end

Israel and the US are able to continue the confrontation, but they are not guaranteed a decisive victory without major costs.

Iran's strategy is to keep the regime alive and increase costs for adversaries. The US and Israel are trying to degrade Iranian military capabilities without engaging in an endless conflict.

Khamenei's death introduces an additional factor of uncertainty into the equation, and the succession to Iran's leadership could result in either a radicalization of the position or the opening of a diplomatic channel.

Phillips pointed out that militarily, Israel retains its qualitative superiority, an active missile defense network and robust US security support, which allows it to sustain repeated air campaigns and defensive operations over a long period of time.

“Its main constraints are domestic resilience (disruption to civilian life, reserve mobilization fatigue) and the cumulative diplomatic and economic costs of a protracted regional conflict, suggesting it can sustain a campaign for years, militarily, but will be under increasing pressure – internal and external – to stabilize the situation long before that,” Phillips said, adding that support from European and British defense contractors it might also dictate, to some extent, how long Israel can sustain this conflict.

“The United States can sustain the current pace of attacks, air and naval deployments, and missile defense support far longer than any of the regional actors from a purely material standpoint, given its global position and industrial base,” he said.

“The constraint is about domestic political will and strategic prioritization,” he noted.