US and Israel attack Iran, killing Khamenei. Tehran launches counterstrikes: Early analysis from Chatham House experts

What do the attacks mean for the regime after the death of supreme leader Ayatollah Ali Khamenei? How will they affect ordinary Iranians, and the region? And what does President Trump hope to achieve? You can read the insights of other Chatham House experts here.

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, formally known as Ansar Allah, has for years benefited from Iranian financial and military support, including assistance from elements of the Islamic Revolutionary Guard Corps.

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, which openly embraces its ideological and organizational ties to Tehran, 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. That domestic narrative provided political cover. 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, particularly as the Houthis attempt to consolidate governance over territories under their control and to preserve fragile understandings with regional actors, including Saudi Arabia.

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.

It remains doubtful that the Houthis will initiate a campaign solely on Iran’s behalf.

That footprint appears to have diminished following Hezbollah’s regional setbacks, but if those external actors retain operational influence, the risk of entanglement increases.

Should the Houthis decide to escalate, they possess meaningful leverage. They can threaten shipping through the Bab al-Mandab strait, a critical chokepoint linking the Red Sea to global trade routes. 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 and raise economic and security costs for the US and its partners.

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.

This article was first published as part of a longer analysis piece by Chatham House experts. You can read it in full here.