At the end of February, the U.S. and Israel launched a sweeping, reckless and almost certainly lawless military campaign against Iran, spawning a growing crisis that much of the world, though apparently not those who instigated it, had predicted. Tactically, their offensive is scoring successes. The opening salvo killed Supreme Leader Ali Khamenei and several senior figures around him. Later strikes targeted missile launch sites and factories, nuclear installations, air defences, naval assets, and buildings used by the Islamic Revolutionary Guard Corps and other state security organs. Strategically, the war’s course so far is a different matter. The Islamic Republic responded almost immediately by targeting Israel, U.S. bases and diplomatic facilities, and U.S. partners in the Gulf, including civilian infrastructure in these states, with missiles and drones, putting them under fire and roiling markets as traffic through the Strait of Hormuz was, in effect, halted except where Tehran itself permitted passage. As the U.S. outlined an array of shifting objectives, the conflict morphed into an asymmetric, attritional battle pitting U.S. and Israeli military superiority against Iran’s determination to widen the battlefield, exploit its adversaries’ growing vulnerabilities and outlast forces it cannot outgun. Though an immediate ceasefire would leave important issues unresolved, achieving it must be the priority of third parties with influence on the U.S. and Iran, lest this already costly war trigger more catastrophic consequences. 

This war of choice did not begin in a vacuum. It follows the twelve-day conflict of June 2025, which ended abruptly but – from the U.S. and Israeli viewpoint – settled little. At the time, Israeli Prime Minister Benjamin Netanyahu contended that the blows landed against Iran’s nuclear and ballistic missile programs had “removed two existential threats”, while U.S. President Donald Trump repeatedly declared Tehran’s enrichment capabilities “obliterated”. Soon enough, those claims were called into question. By late 2025, U.S. and Israeli officials were expressing growing concern about threats they earlier proclaimed to have been subdued: what remained of Iran’s fissile material, how quickly it could revive its uranium enrichment and what it was doing to rebuild its missile stocks. 

Other developments heightened tensions. In December 2025, nationwide Iranian protests violently repressed by the regime prompted unexpected warnings of intervention by President Trump. The U.S. followed up by rapidly bolstering its military assets and personnel in the region – the most massive build-up since the 2003 Iraq war. Though diplomatic efforts between the U.S. and Iran recommenced and appeared to be making progress, the two sides failed to find common ground, with differences concerning both the scope of a putative agreement (whether it would exclusively deal with the nuclear file or cover other Iranian activities) and the specifics of nuclear parameters (in particular the degree, if any, to which Iran would be able to enrich uranium and under what conditions). Whether Trump was using the talks as cover to prepare for a preordained military operation or grew impatient with negotiations that did not yield a quick capitulation, he chose for the second time in a year to initiate hostilities amid a diplomatic endeavour. 

The U.S. offered a laundry list of rationales for the joint military campaign that followed – including pre-empting a seemingly fictional, looming Iranian attack to pre-empt an Israeli strike or retaliate for one – matched by a shifting menu of objectives. Washington variously framed its goal as degrading Iran’s strategic capabilities, achieving regime capitulation (“unconditional surrender”, as Trump has posited), seeking its collapse or destabilisation, or possibly, in a redux of the administration’s January operation to remove Venezuela’s leadership without overturning its government, securing cooperation with certain elements within it. Importantly, Trump, perhaps buoyed by the tactical successes of the June 2025 war and the raid grabbing Venezuelan President Nicolás Maduro, believed that this war would follow a similar pattern of limited duration and costs.

Iran’s response did not conform to Trump’s plans. The Islamic Republic closed ranks at the top of the system – including by elevating Khamenei’s son, Mojtaba, a hardliner, to be the new Supreme Leader – and settled in for what it believes can be a campaign of attrition where it holds, if not a winning hand, at least not a losing one. In practice, Iran has tried to sow chaos in the region through attacks on U.S. partners in the Gulf and squeezing the global economy by, in effect, closing the Strait of Hormuz. It also appears to believe that the costs of the conflict will increase for the U.S. and its partners as stocks of air defence systems, particularly ballistic missile interceptors, are depleted. In its intensity, reach and global reverberations, Operation Epic Fury (or Roaring Lion, as it is known in Israel) has already far eclipsed the June 2025 war.

While in reality the war has delivered the U.S., Israel and Iran their respective wins and losses, all could still claim to have registered sufficient success to bring it to an end, provided they move quickly to do so before events spiral further. Washington’s narrative – which could equally apply to Israel’s gains – would focus on how much damage combined U.S. and Israeli firepower have done to Iran’s nuclear, missile and drone capabilities. President Trump could also point to the decapitation of the regime’s leadership and argue that he has taken on an adversary that other U.S. presidents lacked the mettle to face. This story would not convince the president’s political opponents, but it could help his co-partisans in the run-up to the November midterm elections, in which Trump’s Republican Party might otherwise find itself burdened with a largely unpopular war.

Conversely, continuing the war would mean greater economic havoc, with higher prices at the gas pump, spillover into critical petrochemicals industries and a growing political liability. Nor is it clear what more the war can achieve on the ground other than deepening the present economic and strategic dilemmas. Enrichment sites can be bombed once more, but definitively securing Iran’s fissile material would require the insertion of U.S. and/or Israeli forces, maybe to multiple sites, putting them at risk with no guarantee of successful retrieval. A U.S. invasion aimed at securing the Strait of Hormuz or of occupying Iranian islands in the Gulf or shoreline could deprive Tehran of a vital source of revenue. But it is far from clear that such an assault would be practical: its success would not be foreordained, it would expose U.S. troops to Iranian fire and it could also stoke nationalism among Iranians angered by foreign encroachment. Averting such an outcome and the attendant risks would in and of itself be an important result. 

The Islamic Republic, too, can script a victory narrative: it will have survived a formidable onslaught, demonstrated its resilience and shown that it can destabilise the world economy, conveying the message that pain would be widespread should war resume. In contrast, each passing day of conflict means greater destruction, mounting fatalities and growing opprobrium from its neighbours, which are furious at being Tehran’s primary targets despite their earlier efforts to avert war and which may not be willing to play a de-escalatory role in the future. The war’s continuation would mean further blows to Iranian infrastructure, including electricity and oil facilities and maybe desalination plants as well, which could further compound the misery of a nation that even before the war was contending with impoverishment, power outages, water scarcity and environmental degradation. Limiting the damage is a more realistic way to cap the cost of reconstruction than expecting reparations that are highly unlikely to be forthcoming. 

Yet both sides unfortunately also likely see reason to keep fighting. For the U.S., and also for Israel, ending the war now entails leaving several stated or implicit objectives unmet. The fate of Iran’s fissile material, for example, remains no clearer today than at the conflict’s start. More fundamentally, the Iranian regime is not only still standing but has also exacted real costs. It could emerge emboldened and more aggressive. Even were the U.S. to conclude that it is content to close the proceedings based on the damage already wrought, it is far from clear that Iran would be willing to reciprocate with its own immediate, unconditional truce absent guarantees. At least some in Tehran believe that a prolonged confrontation plays to Iran’s strengths and that stopping now – before the U.S. and the global economy have been made to pay a heftier price – risks inviting renewed attacks down the line. Iran’s leadership has called for assurances that the U.S. and/or Israel will refrain from further offensives, as well as for reparations, a permanent U.S. military retreat from the region and recognition of Iran’s right to uranium enrichment. Some of these demands are doubtless opening positions that even Tehran knows to be unrealistic. But the fear that the U.S. and Israel might resume hostilities at a future date, once they replenish their weapons and interceptor stockpiles, and the conviction that Iran must establish a genuine deterrent through the mayhem it spreads, suggest that Iran might not be willing to stop when Trump decrees an end. Its stated conditions may not be all for show.

For the rest of the world, however, the costs and risks of a prolonged conflict are stark – not just in the Middle East but, as Crisis Group has canvassed, around the globe. From filling up the Russian war chest to disrupting fertiliser supply chains and bringing major hikes in energy costs in Europe and Asia, the Iran war has already reverberated far beyond the Middle East. There is no quick military fix to unblocking the Strait of Hormuz and restoring the vital commerce that flows through it. Even if the conflict ends immediately, it will be some time before traffic through the strait can be restored to previous levels and energy markets calmed. While the U.S. could bring more military might to bear and enlist allies committed to loosening Iran’s grip on the waterway, Iran may have even more energy-related levers at its disposal, not to mention significant military options to counter such a move. Should the Houthis in Yemen enter the fray, they could add to strains on the free flow of navigation by strangling the Bab al-Mandab strait connecting the Gulf of Aden to the Red Sea, yet another maritime chokepoint and an increasingly important alternative route, particularly for Saudi Arabia. Meanwhile, every day of strife profoundly undermines the economy of the Gulf Arab states, which normally are hubs of global commerce, finance and travel. 

As the war deepens and intensifies, other dangers lurk. It is all too easy to imagine a high-casualty event in the Gulf or Israel that could erase any lingering restraint; a resurgence of Iranian-inspired terrorism, in the Middle East, Europe, the U.S. or elsewhere; internal unrest after further regime degradation, which could draw in adjacent countries; or massive refugee flows to the Middle East and Europe. Some of these risks will be magnified by the war’s second major front, which is emerging in Lebanon as Israel seeks to strike a decisive blow against a resilient Hizbollah. Beyond that, there are implications for the war in Ukraine as Russia gains financially from the crisis; potentially for NATO, which Trump has all but threatened to repudiate if allies do not militarily support U.S. efforts to reopen the Strait of Hormuz; and for efforts to improve U.S.-China relations at the forthcoming end-of-March summit, which Trump has suggested he might delay absent Chinese support for his Hormuz initiative.

For these reasons, the priority must be a mutual halt to all attacks by the U.S., Israel and Iran, including those by or against armed groups acting in concert with Tehran. While it is difficult to know who Trump will find persuasive, the Middle East and other Muslim leaders who helped convince him to force Israel’s hand on a Gaza ceasefire in September 2025 may stand the best chance; several are literally on the war’s front line, and their recovery will be integral to any efforts to get the global economy back on track – something that Trump clearly wants to see. 

Gulf capitals are for now, understandably, too concentrated on their own defence and their nerves likely too raw for them to press Trump hard to stop immediately, at least while Iranian attacks on their countries continue, even as they worry about the longer-term consequences of Iran’s readiness to shut down the Strait of Hormuz and striking their cities and infrastructure. Arguably, though, they stand to lose the most from a continued war and could perhaps agree to an effort led by others, including Türkiye and Egypt, for example. Others that might usefully join in entreating Trump include countries deeply affected by disruptions of the Gulf’s energy supplies, like India or China (even as Beijing will surely bat away Trump’s efforts to push it to send warships to the Gulf). Though Republican members of Congress may be loath to cross Trump publicly, private signals to the White House that the president looks increasingly weak and erratic, and is damaging their electoral prospects, could help. Of course, any halt on the U.S. side would need to apply to Israel – something Trump can ensure – and countries holding sway with Tehran would need to make clear that they expect Iran to fully reciprocate. Optimally, this outcome would be enshrined in a UN Security Council resolution, but the formalities are less important than the content. The shooting must stop.

Of course, any such ceasefire would inevitably leave numerous problems to fester. Much like the aftermath of the June 2025 war, none of those that formed the backdrop to the current crisis will have been resolved; indeed, several will have worsened. Outstanding concerns include the fate of Iran’s missile and drone capability as well as of its nuclear program and stockpile of enriched uranium; its support for armed groups across the region that operate outside the law and violate the sovereignty of the states where they are based; Tehran’s relations with Gulf Arab states that have been badly damaged by evidence of Iranian willingness and ability to strike them at will; a U.S. sanctions regime that has helped crush Iran’s economy and will stand in the way of badly needed reconstruction; a heavily militarised U.S. presence in the region that could be reduced in the wake of a ceasefire as a show of good faith but will almost surely still remain at levels Tehran sees as threatening; and Israel’s increasingly maximalist security strategy and the question of whether the U.S. will apply a brake to it. 

They include, too, the broader question of nuclear non-proliferation at a time when Iran’s new leadership could well take a more dangerous view that nuclear deterrence requires an arsenal, not just a potential capability, and when other regional actors might follow suit. Lastly, they include unresolved questions about how the Iranian regime will conduct itself with its own people: by being more responsive to its own society, and thus better placed to rebuild external relationships, secure economic relief and move beyond perpetual confrontation with adversaries abroad and those disaffected at home? Or by hunkering down and intensifying repression?

Without addressing these matters, any pause will be fragile, liable to give way at any time. But these are not issues that can be resolved in a week, or even a month, and right now time is of the essence. The price of a continued conflict, pitting an unconstrained U.S. president against a regime prepared to set the world on fire, is too high. Better to end it immediately, step back from the brink and then seek to address these thorny challenges through renewed diplomacy than try to resolve them now and run the risk of an ever more unmanageable, expanding and perilous war.