Iran's control of the Strait of Hormuz gave it a major leverage over a much more powerful country, the United States, for months. But that control is waning, even though global energy markets have yet to reflect the shift.
Now, another global shipping bottleneck is emerging as a potential conflict front, hundreds of kilometers away, on the other side of the Arabian Peninsula.
The capture of the Red Sea port city of Mocha by the Iran-backed Houthis, as well as their reported advance towards the Bab al-Mandab Strait, have suddenly given Yemen new importance in the wider war.
The timing of these developments is particularly important for Saudi Arabia.
With shipping through Hormuz cut off, Riyadh has increasingly relied on Red Sea routes to get its oil to global markets. Saudi seaborne crude exports through the Bab al-Mandab were reportedly eight times higher from March to mid-July compared to the same period last year.
The Houthis' presence near this strait therefore offers the group a potentially powerful means of threatening Saudi interests and gives Iran another source of influence over regional energy flows and global maritime transport.
This, along with Houthi attacks this week on Saudi energy infrastructure, “has contributed to a further increase in oil prices, which has been Tehran’s goal all along,” said Hamidreza Azizi, senior Iran analyst at the International Crisis Group, based in Belgium.
"Therefore, it can be expected that these developments will further encourage Tehran to adhere to its demands and adopt an even more defiant stance towards the United States," he told REL.
The Houthis’ resurgence also highlights the limitations of the U.S. campaign against the group. Despite weeks of intense U.S. airstrikes last year that targeted the Houthis’ leadership, weapons, and military infrastructure, the group has retained the capacity to mount a major ground offensive and threaten key sea lanes.
But this does not necessarily mean that Tehran ordered the Houthis' offensive.
The Houthis are closely aligned with Iran and have received extensive arms, training, intelligence, and technical assistance from it. Iranian personnel have also reportedly helped direct the Houthis’ military operations. But portraying the group simply as a proxy for Iran risks overlooking what makes the current situation so complex.
"I have always seen the Houthis' relationship with Iran as a strategic partnership, and that is even more true now than before," Azizi said.
The Houthi movement has its own leadership, interests, ideology, and calculations. It emerged from Yemen's own political and sectarian conflicts long before the current confrontation between Iran and the United States.
The group has repeatedly proven that it is capable of making decisions independently of Tehran, even when these decisions ultimately serve Iran's strategic interests.
Despite Iranian support over the years, the Houthis "have their own local and, increasingly, regional ambitions, and see themselves as a regional power," according to Aziz.
The growing weight of the Houthi movement comes at a time when Lebanese Hezbollah, once a powerful partner of Iran, has suffered a severe blow, while Israel continues to dismantle its infrastructure in southern Lebanon.
“In this context, the Houthis’ advances could boost the morale of the Islamic Republic’s supporters within Iran, as well as throughout its regional network,” Azizi argued. “They could also help offset the broader weakening of Iran’s network of influence in the region.”
Iran does not necessarily need to control the Houthis for them to act as a powerful source of influence for Tehran. If the Houthis consolidate their victories along Yemen's western coast, Tehran could benefit from pressure on the Bab al-Mandab without having to directly close another international waterway.
For the Houthis, meanwhile, the war offers its own opportunities.
The collapse of the Yemeni government's defensive line around Mokha gives the group an opportunity to expand its territorial and military position on the Red Sea coast, while strengthening its position in the region.
Any threat to maritime transport could serve both the Houthis' goals in Yemen and Iran's broader confrontation with Washington and its regional partners.
"The fact is that, at this moment, both sides see benefit from simultaneous coordination and escalation," Azizi said.
He added that the Houthi advances spare Iran from having to engage directly in a confrontation with Saudi Arabia, while the Houthi disruption of shipping through the Bab al-Mandab and attacks on Saudi energy facilities "would not have had the same impact they are having now if the Strait of Hormuz were not already under Iranian pressure."
This also puts Saudi Arabia and the United States facing a difficult choice.
A major military response could transform Yemen from a parallel conflict into an active theater of war with Iran, potentially prompting further Houthi attacks on Saudi territory and infrastructure.
But allowing the Houthis to consolidate their position risks leaving a movement hostile to Riyadh in a stronger position near one of the world's key maritime straits.
The dilemma is particularly great because the United States is already trying to manage a conflict whose economic consequences extend far beyond the Middle East.
Disruptions to oil supplies and shipping have raised energy and transportation costs, threatening to fuel inflation and add pressure on an already fragile global economy.
The significance of developments in Yemen, then, lies not simply in the fact that the Houthis have captured another strategic city. The significance lies in the fact that the war may be creating a second point of maritime pressure at a time when the first point, the Strait of Hormuz, has become central to the global economy./REL