The speed of the coastal front’s collapse reflected a deeper weakness in the anti-Houthi camp. An amalgam of government-aligned forces – the National Resistance, Giants Brigades, National Shield and Taiz axis units – were defending the coast but each with separate chains of command and sources of supply. They were not functioning as a single army with integrated reserves and air defence. These formations historically also had separate relationships with outside patrons. Saudi Arabia supports some of them, but the United Arab Emirates had stood up a number of others, and its withdrawal from Yemen in January, following a falling-out with the Yemeni government and Riyadh, left a political and logistical breach that complicated communications within the coalition. The Houthis exploited the gaps. Once its line began to break, the government had no unified command capable of coordinating retreats, reinforcements or counter-attacks.

For the Houthis, the advance’s value lies in the momentum it generates for their domestic agenda, especially in tandem with Iran’s actions in the Strait of Hormuz. They are cash-strapped, but if economic gain had been their principal objective, eastern Yemen would have offered more obvious rewards, given that it comprises the country’s main oil fields. Bab al-Mandab offers something better: influence over a maritime chokepoint at a moment when another, the Strait of Hormuz, is under severe pressure. 

This influence is powerful leverage for both the Houthis in talks with the Saudi-led coalition arrayed against them and for Iran in its showdown with the U.S. In previous negotiations, the Houthis had sought several measures, such as oil revenue sharing and payment of salaries to civil servants in areas under Houthi control. In 2023, shortly before Hamas’s 7 October attacks derailed the deal, they had arrived at an understanding with the Saudi-led coalition that gave them some of what they wanted, for instance opening Sanaa airport to flights to and from five international destinations. Now, emboldened by their march down the coast, the rebels are demanding the items above, but also much more: an end to Saudi support for the Yemeni government, Saudi withdrawal from Yemen and war reparations. They see cross-border attacks and control of heights overlooking Bab al-Mandab – which allows them to impose what they describe as an embargo on Saudi-linked shipping – as the means of achieving these ends. As for Iran, by compounding the disruption of commerce in the Strait of Hormuz, the Houthis’ approach serves the goal of driving up oil prices, thus augmenting international and domestic political pressure on the Trump administration as the U.S. midterm elections in November draw near.

High Stakes for the Saudis

For Saudi Arabia, the Houthi advance sharpens an increasingly dangerous two-strait problem, in which its ships face peril in both the Strait of Hormuz and Bab al-Mandab. Riyadh had tried to prepare for this contingency by strengthening Yemeni government forces, building multilateral deterrence arrangements and keeping channels open with the Houthis and Iran. All three elements of this strategy are now under strain. The coastal front’s breakdown exposed the limits of military consolidation, while international backing remains, for now, focused on sharing intelligence and defending the kingdom itself rather than battling the Houthis. Emerging agreements with Pakistan and Türkiye may bolster Saudi surveillance and air capabilities, but they are unlikely to alter the balance inside Yemen. As for the U.S., President Donald Trump has made clear his reluctance to get involved, saying the Houthis reached out before their offensive to assure Washington they were not looking for another fight like that during the 2023-2025 Gaza war, when they last menaced Red Sea shipping in a systematic way. European and Arab powers will likely support Riyadh, though they also have their limits. Finally, Saudi diplomacy with Tehran and the Houthis has clearly not changed these actors’ calculations.  

For the kingdom, economic stakes are high and rising. The Houthis resumed fire at Saudi-linked vessels in the Red Sea just as they also attacked Saudi energy facilities and Iranian-backed Iraqi Shiite armed groups launched missiles that led to closure of Saudi Arabia’s East-West oil pipeline. On 11 September, after the above-ground pumping stations were hit, Saudi Arabia closed the largely underground pipeline. The conduit had been carrying 3-4.5 million barrels per day toward the Red Sea, helping offset the constriction of the Strait of Hormuz. At the same time, Saudi crude transits through Bab al-Mandab fell from more than 3.5 million barrels per day in early July to near zero in August. Riyadh has been relying more heavily on Egypt, shipping oil by tanker to Ain Sokhna on the Red Sea, then through the Arab Petroleum pipeline 320km north west to the Mediterranean. There, it is reloaded onto tankers headed for Europe, as well as for Asia around the Cape of Good Hope. That lengthy route was already adding time and cost; in addition, too few tankers were available. Even with reports of larger Saudi shipments through Hormuz under U.S. protection, the flow of oil from Saudi Arabia will remain lesser than usual, vulnerable to attack and thus more expensive. The combination of Houthi control of Bab al-Mandab and attacks on energy infrastructure will inevitably have consequences for Saudi Arabia’s economy, regional trade and global energy markets.

Riyadh may conclude that it needs a measure of military success to prevent Houthi gains from becoming entrenched and push the group back toward negotiations. It is likely to combine airstrikes on Houthi positions on the western coast with greater support for Yemeni government forces seeking to recover lost ground, while it looks for alternative ways of shipping out its oil. But Saudi Arabia has little appetite for a return to the large-scale operation that proved so costly after it first intervened to reinstate the Yemeni government in 2015. In the absence of active U.S. involvement, its preferred course will be to enlist willing and able regional and European countries in its efforts to defend Red Sea shipping and its territory. It may also seek their logistical support for its airstrikes in Yemen, while leaving the ground war largely to Yemeni forces and trying to revive its diplomacy with Tehran and the Houthis. That approach could contain the immediate threat, but should it fail, a widening campaign could draw Yemen deeper into the Middle East war, expanding it to both shores of the Red Sea and hardening Saudi Arabia’s position toward Iran.

A Way Out

The danger is that both sides draw the wrong lesson from the latest fighting. The Houthis may conclude that territorial gains and maritime pressure can extract major political concessions, leading them to dig in demanding not just salary payments and reparations but political recognition as a legitimate authority in Yemen. But it is virtually impossible for Saudi Arabia to agree to such steps, which it would see as tantamount to surrender, with all of the attendant political and strategic costs. Saudi Arabia and the Yemeni government may, in turn, try to reverse their fortunes by enlisting more countries on behalf of their campaign and opening several fronts at once, hoping that the Houthis will relent, notwithstanding the rebels’ record of resiliency under duress. Either course could tip Yemen back toward full-scale war and worsen what is already a catastrophic humanitarian crisis in the country. 

The first objective should thus be to freeze the military contest in place. That would entail the Houthis halting their offensive in Yemen and stopping attacks on Saudi territory and shipping. Meanwhile, Saudi Arabia and the Yemeni government would refrain from opening new fronts and pair measures designed to defend their positions with steps that offer the Houthis incentives for restraint. These would include allowing regular commercial flights from Sanaa to the five destinations agreed upon in 2023 and progress on economic arrangements such as payment of civil servants’ salaries. Oman is best placed to broker such a deal, while opening space for the parties to return to negotiations on broader political issues. But Iran, too, should realise that the slide toward broader war could jeopardise its remaining contacts with Saudi Arabia and further nudge other regional countries to align against it. Rather than encourage the Houthis along their current path, it should use its leverage to push for a halt to attacks on Saudi Arabia and an end to further territorial conquest in Yemen. 

Of course, given how closely the Yemen conflict is connected to the U.S.-Iran confrontation, any such de-escalation would be greatly facilitated by easing tensions between Tehran and Washington – and any sustainable de-escalation likely would require as much. Efforts to that end have failed so far, but events in Yemen should serve as a reminder of the urgency. European and regional states should double down on collective efforts to revive a version of the U.S.-Iran memorandum of understanding reached in June, focused on removing the double blockades on the Strait of Hormuz; issuing waivers for Iranian energy exports; and freezing both new U.S. sanctions and Iran’s nuclear program. For all, the aim should be to work in concert to prevent the confluence of the two fronts from provoking an even wider war that could embroil other regional and international actors in the Red Sea.