Iran launched roughly 180 ballistic missiles at Israel on 1 October, its second direct attack on the country this year and a major escalation from the shadow war that defined their relationship for decades. Iran said the attack was retaliation for Israel’s killing of Hassan Nasrallah, Hamas political leader Ismail Haniyeh, and senior Iranian and Hezbollah figures. Israel intercepted many of the missiles with assistance from the United States and regional defence systems, although some struck Israeli military installations and a Palestinian man was killed by falling missile debris in the West Bank. Prime Minister Benjamin Netanyahu has said Iran “made a big mistake” and will pay for the attack. Iran has warned that an Israeli response will produce another Iranian response. The strategic problem is now almost perfectly circular: Iran attacked because it believed failing to retaliate would weaken deterrence; Israel believes failing to retaliate against that attack would weaken deterrence; Iran says it must retaliate again if Israel retaliates. Each side is therefore attempting to restore deterrence through behaviour that gives the other side another reason to restore deterrence.
This is why deterrence is much easier to describe retrospectively than to manage during an active crisis. In theory, deterrence means convincing an adversary that the expected cost of an action exceeds its expected benefit. Iran wants Israel to believe that killing senior Iranian and allied leaders carries a risk of direct missile attack. Israel wants Iran to believe that launching missiles at Israeli territory produces unacceptable consequences. Both propositions can be rational individually. The problem appears when both deterrent threats are activated simultaneously. Punishment designed to prevent the next attack becomes the cause of the next attack, producing an escalation loop in which every actor can describe its own violence as defensive retaliation.
Iran’s decision is understandable through the severe deterioration of its regional position during September. Hezbollah, Tehran’s most important non-state ally, suffered extraordinary losses: communications systems were penetrated, senior commanders were killed and Nasrallah himself died in an Israeli strike. Israel then began ground operations in southern Lebanon. If Tehran had remained passive throughout this sequence, it risked signalling that the network of armed groups it spent decades constructing could be degraded without meaningful direct Iranian intervention. Iran therefore faced a credibility problem not only with Israel but with its own partners. Hezbollah, Iraqi militias and the Houthis need to believe alignment with Tehran provides something beyond ideological solidarity.
This exposes a fundamental weakness in proxy strategy. Iran’s regional network gives it strategic depth because partners can impose costs on adversaries while Iran avoids direct conventional war. Yet proxies are valuable only if the sponsor can preserve them. Once an adversary begins destroying the network faster than Iran can replenish it, Tehran must choose between direct escalation and watching the credibility of the network deteriorate. Strategic depth creates strategic obligations. The more Iran relies on allies for deterrence, the harder it becomes to remain detached when those allies face severe losses.
Israel’s campaign therefore appears aimed partly at separating the network into components and demonstrating that Iran cannot protect each one simultaneously. Hamas has been severely weakened militarily in Gaza. Hezbollah has lost much of its senior leadership. Iranian commanders have been targeted in Syria and elsewhere. Israel’s objective is not simply destroying weapons but changing expectations across the network: membership in the axis of resistance should become increasingly costly.
Iran’s missile attack attempts to reverse that signal by demonstrating that attacks on the network can eventually produce direct Iranian retaliation. The result is a transition from proxy deterrence towards direct deterrence. That is strategically significant because direct exchanges contain much less ambiguity. When Hezbollah fires rockets, Tehran can maintain some distance from the decision. When ballistic missiles leave Iranian territory towards Israel, attribution is immediate and the Israeli government can respond directly against Iran.
The barrier separating the shadow war from interstate war has therefore weakened dramatically in 2024. Iran and Israel exchanged direct attacks in April and again this week. Actions that would have appeared unprecedented a year ago now possess recent precedent. This is threshold erosion: once a behaviour occurs without catastrophic consequences, leaders become more willing to consider it again.
That does not mean direct war is inevitable. It means the political cost of choosing direct attack has fallen. Governments can tell themselves, correctly, that the previous exchange remained contained.
That is precisely what makes the situation dangerous.
The previous exchange may have remained contained because damage was limited, diplomacy was intense and both governments deliberately chose restrained responses. Those conditions are not guaranteed to repeat. A ballistic missile could strike a crowded residential building. An Israeli attack could kill senior Iranian political leaders. A strike on energy or nuclear infrastructure could generate economic or existential fears much greater than those produced in April.
Escalation risk is nonlinear. The tenth exchange does not necessarily resemble the first nine.
Israel now needs to choose what kind of retaliation produces the greatest expected security benefit. Potential targets vary enormously in strategic meaning. Striking Iranian military facilities would communicate punishment while keeping the confrontation closer to the military domain. Attacking oil infrastructure could impose substantially larger economic costs on Iran while potentially affecting global energy markets. Attacking nuclear facilities would carry the greatest strategic significance because Tehran could interpret it not merely as retaliation but as an attempt to destroy a central national-security programme.
The target therefore communicates intent as well as capability.
This is why American influence matters. President Joe Biden has publicly opposed an Israeli attack on Iranian nuclear facilities and suggested that any response should be proportionate. Washington simultaneously participated in defending Israel from Iran’s missile barrage. The distinction is important: American commitment to Israeli defence does not automatically imply American support for every offensive response Israel might choose.
That separation is essential if alliances are to reduce rather than amplify escalation. An ally providing unconditional support can unintentionally create moral hazard. If one state believes another will absorb much of the military and diplomatic cost of its decisions, it may take greater risks than it would alone. Conditionality therefore is not necessarily abandonment. It can be part of alliance management.
The United States faces its own credibility problem, however. If Washington repeatedly urges restraint while Israel concludes that restraint allows Iran and its proxies to rebuild, American advice becomes less persuasive. Influence requires offering an alternative mechanism through which Israel’s security objective can be achieved. Telling a government not to retaliate is easier than explaining how another Iranian missile attack will be prevented.
This is why deterrence by denial remains important. Israel and its allies intercepted much of Iran’s barrage, reducing casualties dramatically. Successful air defence lowers the immediate political pressure for overwhelming retaliation because the attacker fails to create equivalent physical damage. Defensive capability therefore creates diplomatic space.
But missile defence is not free. Iran can launch large numbers of comparatively cheaper weapons while Israel and the United States expend sophisticated interceptors. The defender therefore confronts a cost-exchange problem. Winning every interception can still become expensive if attacks are repeated frequently enough.
Stockpiles matter more than headline interception percentages.
A defence system capable of defeating one enormous attack may not be able to defeat one every week indefinitely.
This makes destroying launch infrastructure attractive, but again creates escalation risk.
Iran’s own vulnerability is substantial. Israel possesses superior conventional air power and intelligence capabilities, while Iran’s critical energy infrastructure is geographically concentrated. Tehran therefore knows that sustained conventional conflict could impose enormous economic costs. Its oil exports provide essential government revenue, and disruption around the Persian Gulf could affect global energy markets.
This creates a degree of mutual economic deterrence. An Israeli attack on Iranian oil infrastructure could hurt Iran severely but also raise international oil prices, affecting economies far beyond the conflict. Iran could threaten shipping or energy infrastructure elsewhere in the Gulf, multiplying the shock. The global economy therefore becomes a third party whose vulnerability constrains military options.
The Strait of Hormuz illustrates this interconnectedness. A significant share of internationally traded petroleum passes through a narrow maritime corridor beside Iran. Any serious disruption would transmit Middle Eastern escalation rapidly into fuel prices, inflation and central-bank policy around the world. A missile exchange between two states therefore can become a household-cost shock in countries thousands of kilometres away.
This is network power through geography. Iran’s conventional military capabilities are weaker than America’s or Israel’s, but its location gives it leverage over critical energy routes. Strategic power therefore does not derive only from GDP or weapons. Control over chokepoints changes bargaining strength.
The nuclear question remains the most dangerous because Israel has long regarded the possibility of a nuclear-armed Iran as an unacceptable security threat. Iran insists its nuclear programme is peaceful, while its enrichment activities and reduced cooperation with international monitoring have generated substantial concern. Israeli policymakers may view Iran’s current regional weakness as an opportunity to strike nuclear infrastructure while Hezbollah’s ability to retaliate has been reduced.
That logic is strategically understandable and potentially catastrophic. Preventive war attempts to destroy a future threat before it becomes stronger. Its problem is that attacking nuclear infrastructure can strengthen the target’s incentive to acquire nuclear weapons afterwards. Tehran could conclude that remaining non-nuclear leaves it vulnerable to exactly the attacks a nuclear deterrent might prevent.
This is the non-proliferation paradox of preventive attack. Destroying physical nuclear infrastructure can delay a programme while increasing political determination to rebuild it secretly and weaponise it. Whether the delay exceeds the motivational effect depends on technical damage, political change and international monitoring.
Iran’s regional strategy itself partly developed because conventional military asymmetry made direct competition with Israel and the United States difficult. Proxies, missiles and potentially nuclear latency provide alternative forms of deterrence. Destroy one layer and Tehran may invest more heavily in another.
Security competition therefore behaves like water under pressure: blocking one channel can redirect effort elsewhere unless the underlying threat perception changes.
This is why a purely military solution to the Iran-Israel conflict remains elusive. Israel can weaken Hezbollah. Iran can rebuild proxy networks. Israel can attack missile facilities. Iran can disperse them. Israel could damage nuclear infrastructure. Iran could rebuild or accelerate weaponisation. Each tactical action changes capabilities without necessarily changing the political preferences generating competition.
The underlying conflict concerns regional power, Israel’s security, Iran’s revolutionary ideology, the Palestinian question, American military presence and the structure of Middle Eastern alliances. No air strike can resolve all of those simultaneously.
Military force can still change bargaining conditions.
That distinction matters.
Force is not useless because it cannot solve everything.
It becomes dangerous when tactical effectiveness is mistaken for political resolution.
The killing of Nasrallah demonstrates this clearly. Israel removed one of its most capable adversaries and severely weakened Hezbollah’s command structure. That is a real strategic gain. Iran responded with ballistic missiles. The gain therefore altered the conflict rather than ending it.
This is strategic adaptation.
Every successful action changes the adversary’s incentives.
The correct question is not “did the strike work?” but “what system of behaviour did the strike produce afterwards?”
That is a much harder standard.
Iran’s missile attack now presents Israel with the same problem. A large retaliatory strike might destroy substantial Iranian capability. If it produces another larger Iranian attack, accelerates nuclear development and pulls the United States into war, tactical success could coexist with strategic deterioration.
Conversely, an excessively limited response could persuade Tehran that large ballistic-missile attacks are tolerable.
There is no costless option.
This is what makes proportionality strategically useful, beyond its legal and moral dimensions. A calibrated response can impose enough cost to preserve deterrence while leaving the opponent an off-ramp. The objective is not matching damage mathematically. It is influencing the next decision.
Face-saving matters here. Iran needs a narrative allowing it to stop after retaliation. Israel needs a narrative allowing it to stop after its response. Diplomacy works partly by constructing those narratives.
In April, both sides eventually did this. Iran claimed its attack demonstrated capability. Israel carried out a limited strike near Isfahan that demonstrated penetration of Iranian air defences without producing mass destruction. Both governments could tell domestic audiences they had responded.
The challenge is recreating that equilibrium after a much more consequential sequence of events.
Nasrallah is dead.
Israel is operating inside Lebanon.
Iran has launched another major missile barrage.
The political stakes are higher.
The credibility costs of restraint therefore appear higher too.
This is why the next Israeli response matters disproportionately. It will establish another precedent for what direct Iranian attack produces. Iran’s reaction will establish another precedent for what Israeli retaliation produces.
Repeated interaction gradually creates an informal escalation ladder.
The danger is that each rung becomes normal immediately after being used.
The region therefore needs to stop the ladder from extending faster than governments learn where it ends.
Iran and Israel both possess legitimate reasons, within their own strategic models, to believe restraint can be interpreted as weakness.
That belief is exactly what makes restraint difficult.
But deterrence is not measured by whether every attack receives a larger attack.
It is measured by whether future attacks become less likely.
Those are not the same thing.
Sometimes punishment produces deterrence.
Sometimes punishment produces retaliation.
The strategic skill lies in recognising which environment you are in.
Iran’s attack on 1 October suggests the region is increasingly in the second.
If Israel responds, Iran has already promised another response.
If Iran responds again, Israel will face the same credibility calculation.
At some point, one actor must decide that preserving deterrence does not require answering every rung with another rung.
Otherwise the logic becomes self-defeating.
Each government will continue saying it is acting to prevent the next attack while creating the political reason for the next attack.
That is not stable deterrence.
It is an escalation loop with a deterrence vocabulary.
The Middle East has spent most of 2024 demonstrating how close those two concepts can become.
The next several days may determine whether Israel and Iran can separate them again.
