Killing Khamenei; Early analysis from Chatham House experts
US and Israel attack Iran, Tehran launches counterstrikes:
What do the attacks mean for the regime after Iranian state media confirmed the death of supreme leader Ayatollah Ali Khamenei? How will they affect ordinary Iranians, and the region? How will Iran respond? And what does President Trump hope to achieve? Chatham House experts provide insights.
The United States and Israel launched multiple air strikes across Iran on Saturday 28 February, striking multiple targets and killing the country’s supreme leader, Ayatollah Ali Khamenei.
US President Donald Trump announced ‘major combat operations in Iran’ and said later on Saturday that Khamenei had been killed.
Iranian state media announced the supreme leader’s death early on Sunday.
Trump said: ‘Our objective is to defend the American people by eliminating imminent threats from the Iranian regime’. He said Iran was pursuing a nuclear weapons programme – a claim denied by Tehran. ‘They can never have a nuclear weapon,’ he said.
Both Trump and Israeli Prime Minister Benjamin Netanyahu urged Iranians to pursue regime change. In a message addressed to ‘the great, proud people of Iran,’ Trump said: ‘The hour of your freedom is at hand…when we are finished, take over your government, it will be yours to take. This will be, probably, your only chance for generations.’
Iran launched retaliatory strikes against Israel, and across the region.
Here Chatham House experts provide early analysis of the meaning of the strikes for Iran, the region and the world.
Dr Sanam Vakil, Director of the Middle East and North Africa Programme:,
There is no doubt that we are at a critical moment, one that will reshape the region and profoundly affect Iran itself. The Iranian people will bear the greatest cost.
For Tehran, this is not a short twelve-day war or a contained round of escalation that can be paused and reset. This new stage of conflict is existential and clearly about regime survival. It is also unlikely to end quickly.
President Donald Trump campaigned against regime change wars and was sharply critical of the 2003 invasion of Iraq. As recently as his Gulf visit in May 2025 he promised that those days were over.
Yet what we are seeing now suggests something far more ambitious than coercive diplomacy. Trump has framed this confrontation as the culmination of a 47-year adversarial relationship between the US and Iran, dating back to 1979, arguing that the Islamic Republic has consistently undermined US interests and destabilized the region.
These strikes are intended to do more than bring Tehran back to the negotiating table. Trump appears to be attempting to redefine the terms of that 47-year conflict and secure his place in history by trying to resolve it decisively.
The US and Israel have targeted nuclear facilities, ballistic missile infrastructure and radar installations, alongside specific strikes on leadership compounds and elements of Iran’s military command structure.
This is not limited to degrading capabilities at the margins. It is a direct blow to the state’s security architecture and governing apparatus. The parallel with the 2003 Iraq war is difficult to ignore. That war demonstrated that collapsing or attempting to collapse a regime is far easier than shaping what follows.
Trump has spoken about freedom for the Iranian people. That is a powerful message rhetorically, but it is difficult to see how genuine political transformation develops under conditions of sustained war, chaos and potential fragmentation.
External military pressure may weaken a regime, but it does not automatically build a viable alternative. Even if such an outcome benefits Israel strategically by removing a hostile government, it does not mean the immediate result for Iranians will be stability or something better. The space between regime collapse and democratic consolidation is historically the most dangerous phase.
Iran, moreover, is not Iraq in 2003. It has more cohesive state institutions, a deeply embedded ideological structure and regional networks that extend well beyond its borders.
Even if parts of its leadership and command structure are degraded, the Islamic Republic has experience regenerating under pressure. While talks were ongoing, Tehran was simultaneously preparing for this contingency. Its response came within four hours of the first strikes, suggesting pre-planning and coordination.
Strikes across Israel and against Gulf states indicate a deliberate decision to externalize the conflict rather than absorb the blows quietly.
From the regime’s perspective, if survival is at stake, there is little incentive to keep the confrontation geographically contained. Expanding the theatre raises costs for US partners, and signals that any attempt to dismantle the system will reverberate across the region. There is also a real possibility that Iran’s allies, including the Houthis and perhaps others within Iran’s broader network, will be drawn in more directly.
Bronwen Maddox, Director of Chatham House:
You don’t do regime change from the air.
The risk is that the US already has multiple stated objectives – ending Iran’s nuclear weapons programme, missiles, and supporting Iranian protesters. That is a recipe for confusion.
Iran’s neighbours and the Gulf states will be very uncomfortable at the strikes on them, presumably from Iran, this morning. Iran is trying to make them look complicit with the US in the eyes of their populations.
Even if supreme leader Ayatollah Ali Khamenei went, Iran’s Islamic Revolutionary Guard Corps (IRGC) are a real military-industrial complex running much of the economy, and one of them could end up in charge.
President Trump talked about Iran’s protesters. But the protesters already feel betrayed.
Tens of thousands were shot in the wave of demonstrations earlier this year, and they do not want to come out again. Trump saying weeks ago that ‘help is on its way’ was not enough to save them. And they still lack a leader.
This has the makings of the kind of enduring conflict that Trump said he didn’t want.
Laurel Rapp, Director of the US and North America Programme
President Trump’s declaration of war against Iran to depose the regime is a high-risk break with decades of US policy towards Tehran.
The American strategy appears wholly predicated on the untested proposition that the Iranian people will quickly rise up – a huge gamble. Should a massive revolt fail to materialize, the Trump administration will face a fork in the road: fold or double down.
In abandoning negotiations for force, the US opens an uncertain and dangerous path ahead, with grave risks for US military personnel in the ballistic missile strike zone, and US partners vulnerable to retaliation from Iranian proxies.
It is undeniable that Iran’s nuclear ambitions, stockpile of ballistic missiles, and regional militia proxies pose a threat to the United States and its partners. The Iranian regime has cultivated these tools for decades, at great cost to the Iranian people. Multilateral sanctions and periodic US strikes against Iranian proxies sought to bind Iran’s hands.
The Joint Comprehensive Plan of Action (JCPOA) successfully cabined Iran’s nuclear problem until the US withdrew. It was a strategy to manage symptoms versus address root causes, and – though imperfect – it prevented a risky and grinding US military entanglement.
President Trump ran on a platform of ending forever wars and bringing US troops home.
The White House National security strategy (NSS), published just two months ago, affirms that the ‘days in which the Middle East dominated American foreign policy in both long-term planning and day-to-day execution are thankfully over.’ Both accurately reflect American public attitudes, with little appetite for a war of choice in the Middle East.
The initial US military campaign appears limited to air strikes but – if the lessons from Afghanistan, Iraq, and Libya are instructive – aerial bombardment alone is unlikely to topple a regime absent mass defections from Iran’s deeply entrenched military command.
Requirements typically include a significant commitment of ground troops, relentless diplomatic coordination among partners, and careful planning and stewardship of successor structures. These are the ingredients of nation-building that the American public has rightfully rejected.
If the past year of US foreign policy decision-making is predictive of the days ahead, Trump’s desire to project strength and ‘win’ may quickly supplant the popular mandate that brought him back to power – as well as his own strategy.
Every recent US president has tried to, finally, redirect US attention beyond the Middle East. To Asia. To the Western Hemisphere. None has succeeded.
Dr Marion Messmer, Director of the International Security Programme:
President Trump has said these attacks are intended to prevent Iran from acquiring nuclear weapons. After the US air strikes in June 2025, the US government said they had significantly degraded Iran’s nuclear programme.
The strikes also come at a time when several US officials have called for regime change in Iran.
The US seems to have targeted sites that either have a connection with Iran’s nuclear research, or are missile production and storage sites, seeking a further degradation of Iran’s military capabilities.
The Iranian government is already weakened after two years of on-and-off conflict escalation. But it is striking back. Israel and Qatar have reported intercepting incoming Iranian missiles. This means that even with a weakened Iranian government, there is a risk of this conflict escalating and drawing other states in.
Beyond the risk of war in the Middle East, the attack set a worrying precedent by continuing a pattern: striking when negotiations are not going as Washington would like them to. This reduces the likelihood that other states will be willing to enter into negotiations with the US in future, if there is always a risk of the US escalating to military attack.
Professor Marc Weller, Director of the International Law Programme:
Professor Weller examined President Donald Trump’s stated justifications for the strikes – including Iran’s reported killings of internal protesters, which was given extensive global media coverage in January, Trump’s repeated assertions – denied by Iran – that the Tehran regime is pursuing a nuclear weapons programme – and historical attacks against US targets which Trump blamed on Iran. Professor Weller concludes:
It is clear that the US cannot claim to have acted in its own defence.
It is alleged that Iran may derive an intercontinental ballistic missile capacity from its ongoing space programme within a decade. However, it does not at present have the capacity to mount an intercontinental attack against the US. There were also no imminent threats of Iranian offensive action against US assets in the Middle East.
President Trump’s claim that Iran’s alleged nuclear weapons programme amounts to an imminent threat to ‘core US security interests’ does not change this picture.
After the strikes against Iran of last June, President Trump confirmed that Tehran has lost its capacity to pose a nuclear threat, at least in the mid-term. Even if Iran had the ability to reconstitute its nuclear programme over time, there was no imminent threat requiring a military response at this time.
In addition, there was no necessity to act. Disarmament talks with Iran were ongoing and, by most accounts, they were progressing, at least on the issue of enrichment of Uranium necessary for achieving a nuclear capacity.
While Iran was unwilling to engage in concessions on other demands put by the US, it is not possible to argue that there was no means other than the use of force available to address the alleged nuclear threat.
Focusing on self-defence on behalf of Israel, rather than the US itself, does not really change this picture. True, Israel is within range of Iranian missiles and drones. But there was no indication of an imminent armed attack against Israel that might have triggered the claim to ‘pre-emptive’ action in self-defence advanced by Israel.
President Trump also points to the array of hostile groups around Israel’s borders, including Hezbollah in Lebanon, Hamas in Gaza, and the Houthi in Yemen.
These have been supported by Iran. But again, this threat had been seriously weakened through Israel’s previous armed action. Moreover, there was no indication of an imminent attack emanating from these groups and even this would not have justified armed action against Iran.
Overall, therefore, this instance represents a further instance of the US acting unilaterally to achieve its own broad security aims, along with supposed aims of its allies and even the global community, without having achieved a global mandate from the UN.
Farea Al-Muslimi, Research Fellow in the Middle East and North Africa Programme:
While the Houthis are widely viewed as one of Iran’s closest remaining regional allies – particularly after the weakening of Hezbollah in Lebanon – it is far from certain that they will intervene militarily.
The Yemeni militia has for years benefited from Iranian financial and military support. Iran has helped develop the Houthis’ ballistic missile and drone capabilities, and Yemen has at times served as an arena through which Tehran could pressure its regional adversaries indirectly while claiming deniability.
However unlike Hezbollah, the Houthis have historically been sensitive to accusations that they are merely an Iranian proxy even if that – throughout the years – proved to be true.
Yemen does not offer Iran the same theological, social, or political depth that exists in parts of Lebanon or Iraq. On the contrary, suspicion of ‘Persian’ influence has deep historical roots in Yemen. With the exception of a limited ideological circle within the Houthis, overt identification with Iran remains unpopular. This explains why Houthi leaders have often denied or downplayed the extent of their relationship with Tehran, and have reacted sharply when they are labeled an Iranian tool.
Domestic calculation therefore remains central to any decision to escalate. The Houthis cannot afford to frame a war as one fought simply on behalf of Iran.
Previous attacks on Israel and on Red Sea shipping were justified internally through the lens of solidarity with the Palestinian cause – an issue that commands broad sympathy among Yemenis, including among the Houthis’ rivals. A direct intervention in defence of Tehran would not carry the same unifying legitimacy.
Moreover, the movement is still recovering from significant US strikes last year that degraded parts of its military infrastructure. Entering a new confrontation at a moment of relative fragility would carry serious risks.
At the same time, the Houthis are not inherently risk-averse. The group has historically thrived in wartime conditions, using conflict to sustain mobilization, reinforce ideological cohesion, and postpone difficult political compromises. War can serve its internal logic.
This does not mean it will automatically intervene, but it does mean that controlled escalation remains an available instrument, especially if it can be framed as self-defence rather than solidarity.
Two factors could significantly shift the calculation. The first, and more likely, would be direct military strikes against Houthi targets. In that scenario, intervention would become less a matter of choice and more one of perceived survival.
The second concerns the residual presence of Iranian and Hezbollah-linked operatives in Yemen. In the past, personnel affiliated with the IRGC and Hezbollah have reportedly assisted in launches toward Saudi Arabia, at times pushing escalation beyond what Houthis preferred.
That footprint appears to have diminished following Hezbollah’s regional setbacks, but if those external actors retain operational influence, the risk of entanglement increases.
They can resume drone and missile attacks against Israel, as well as target US military facilities or Western-linked infrastructure within range. Such actions would not fundamentally alter the balance between Washington and Tehran, but they would expand the theatre of conflict.
For now, however, it remains doubtful that the Houthis will initiate a campaign solely on Iran’s behalf. Their decision-making is shaped as much by domestic legitimacy and strategic self-preservation as by regional alignment. Unless directly drawn in, they are more likely to calibrate their involvement carefully rather than commit to open-ended escalation.
*Chatham House is an international affairs think-tank based in London.
Source: https://www.chathamhouse.org/2026/02/us-and-israel-attack-iran-early-analysis-chatham-house-experts