The Prospects of a Second War between Israel and Iran

The possibility of a second full-scale war between Israel and Iran has become one of the most serious and destabilising contingencies in contemporary international relations. Both states perceive themselves as locked in an existential contest that spans ideology, regional order, technological supremacy and the control of strategic space stretching from the Mediterranean to the Persian Gulf. While each has engaged in periodic clashes—most commonly through proxies, covert action or strikes in third countries—the question remains whether the present equilibrium is sufficiently robust to avert a broader confrontation. Understanding the prospects of such a war requires a careful examination of the shifting military, political and diplomatic conditions that constrain or encourage escalation.

Strategic Perceptions and the Logic of Deterrence

Israel views the Islamic Republic of Iran as its most determined adversary, not least because Tehran’s political theology denies Israel’s legitimacy. Iran, for her part, considers Israel an extension of Western imperial reach into the Middle East and a major obstacle to her own aspirations for regional influence. This mutual perception of threat constrains diplomacy and sustains a system of reciprocal deterrence.

Israel’s deterrent posture rests upon three pillars: her overwhelming technological superiority, her advanced air power and missile defence network, and her presumed nuclear capability. Iran relies instead upon strategic depth through proxies, long-range missiles, dispersed command structures and, increasingly, her own advances in drone warfare. Each side believes that war would be catastrophic but also that failure to demonstrate resolve invites strategic encirclement.

The result is a deterrence system that is neither stable nor symmetrical. Israel believes she must strike pre-emptively if certain red lines are breached—such as Iranian nuclear breakthrough or a large-scale mobilisation by Tehran’s regional allies. Iran, lacking equivalent high-precision offensive capabilities, relies more heavily on signalling and on the threat of attritional retaliation across multiple fronts. This imbalance makes miscalculation a persistent risk.

The Shadow War and its Limits

For more than a decade, Israel and Iran have engaged in a sustained but largely covert conflict. Israel has struck Iranian weapons shipments in Syria, sabotaged nuclear facilities inside Iran, and targeted senior Revolutionary Guard commanders responsible for regional operations. Iran has responded through cyber attacks, asymmetric operations, and the arming of Hezbollah, Hamas and various militias in Iraq and Yemen.

This shadow war has served a purpose: it allows each side to impose costs on the other while preserving plausible deniability and avoiding the public humiliation associated with open failure. However the very success of this model encourages escalation. Each operation encourages a compensatory move, and the increasing visibility of these strikes—particularly those in Damascus and across Syria—has made it harder for either state to ignore them. The assassination of senior Iranian commanders, or major damage to strategic infrastructure, carries political consequences that Iranian leaders cannot easily absorb.

The shadow war therefore mitigates conflict only up to a point. It creates a ladder of escalation that is shallow at the bottom but steep at the top. Once a certain threshold is crossed—likely through a mass-casualty attack or the destruction of critical military assets—the step from the covert to the overt may become unavoidable.

Nuclear Stakes and Red Lines

At the centre of Israeli strategic anxiety lies Iran’s nuclear programme. Tehran insists upon the civilian nature of her nuclear ambitions, but Israeli security planners regard the programme as inherently military in character. Even if Iran refrains from weaponisation, her status as a threshold nuclear state would profoundly affect Israeli strategic calculus, potentially constraining Israel’s deterrence posture and allowing Iran greater freedom to pursue regional objectives.

Israel has stated repeatedly that she will not tolerate an Iranian nuclear weapon. Whether Israel would launch unilateral strikes on Iranian nuclear facilities is a matter of continuing debate, but recent history suggests she is prepared to act pre-emptively when she perceives existential risk. Iran, anticipating this possibility, has hardened her facilities, diversified her enrichment sites, and developed air defences capable of deterring all but the most sophisticated operations.

A new strike on Iranian nuclear sites is therefore not merely a tactical choice but a strategic trigger. Iran would interpret such an attack as an existential assault, and her response would almost certainly be massive, involving ballistic missile attacks (of which Iran claims to have thousands), drone swarms, regional proxy mobilisation, and the disruption of maritime trade in the Gulf. Israel, facing such retaliation, would escalate further. The chain of events could slide rapidly beyond the ability of external powers to control.

Regional Proxies and the Multi-Front Risk

The most likely scenario for a second war involves not a direct Israeli strike inside Iran but a spiral triggered by proxy conflict. Hezbollah, Iran’s principal ally, possesses a missile arsenal far larger and more sophisticated than it did during the 2006 war with Israel. A major confrontation in Lebanon—whether provoked intentionally or arising from cumulative skirmishes—could draw Iran more directly into the conflict. Israel, facing saturation attacks on her cities, may seek to expand the theatre to halt the flow of Iranian weapons.

Simultaneously, further conflict in Gaza or the West Bank, missile launches from Iraqi militias, and further attacks in the Red Sea by the Houthis (the Iran-aligned Shia militia in control of much of Yemen) would transform the confrontation into a regional war fought along Iran’s carefully cultivated arc of influence. Iran’s strategy relies upon precisely this interlocking network; Israel’s strategy is to prevent it from becoming a cohesive, coordinated front. The risk is that a spark in any single theatre ignites the whole structure.

External Powers and the Diplomatic Containment System

The United States remains Israel’s principal ally and Iran’s principal adversary. Washington has no desire for a regional war that would disrupt global energy markets, dislocate maritime trade, and drag American forces into a conflict without clear end. The Gulf states, although hostile to Iranian influence, also fear regional conflagration. European powers likewise prefer continued containment.

This international reluctance to accept a war exerts significant pressure on both sides. American diplomacy has repeatedly sought to restrain Israeli actions that could widen the conflict, while simultaneously supporting Israel’s defensive posture. Iran, aware of her economic vulnerability, attempts to avoid crossing American red lines even while challenging them.

However external pressure is not a guarantee of stability. If Israel believes she faces an existential threat, she may act without American consent. Conversely, if Iran’s leadership feels cornered—economically isolated, domestically unstable or militarily humiliated—she may escalate as a matter of regime survival.

The Threshold Question: Is a Second War Likely?

A second full-scale war between Israel and Iran is not inevitable, but nor is it remote. The prevailing strategic environment is fragile. Each state believes she is defending essential interests. Each possesses military capabilities that encourage the illusion that victory, or at least a favourable stalemate, might be achievable. Each also relies on red lines that the other side may not fully understand.

The most likely path to war is inadvertent escalation through proxy conflict. The least likely—but most dangerous—scenario is a direct Israeli strike on Iranian nuclear facilities, followed by an Iranian strategic retaliation.

Nevertheless, the incentives for caution remain powerful. Iran fears regime destabilisation. Israel understands the risks posed by a multi-front missile war. The United States continues to invest diplomatic capital in preventing escalation. The regional economic consequences of war would be severe for all major actors.

The prospect, therefore, is neither imminent nor avoidable. It is a standing risk: a structural weakness in the regional order that could be triggered by miscalculation or political shock. The challenge for diplomacy is to maintain channels of communication, reinforce deterrence, and prevent localised incidents from accumulating into strategic catastrophe.