The fighting between Saudi Arabia and Yemen’s Iran-aligned Houthis has sharply escalated in the past two weeks, with the militia making their biggest territorial gains in years.On September 10, they captured the strategic Red Sea port of Mocha (after which Mocha the coffee is named) along with other territory along Yemen’s western coast. By September 17, Ansar Allah, the official name of the Houthi militia, effectively controlled much of Yemen’s Red Sea coast.Thus, while the Houthis are gaining more power against Yemen’s official government, which Riyadh backs, they are also in the position to disrupt Saudi oil flow on its western coast, at a time its eastern coast shipping is already suffering because of the Strait of Hormuz blockade. The global oil price has already crossed $100 per barrel, up from $70 in June 2026The Houthis have also launched missiles and drones at Saudi territory, including attacks on energy infrastructure. Saudi Arabia has responded with airstrikes and warnings of stronger action.On paper, Saudi Arabia has defence partnerships with multiple key players in the region. The US-Saudi Strategic Defense Agreement was signed on November 18, 2025; Saudi Arabia and Pakistan signed their Strategic Mutual Defense Agreement (SMDA) on September 17, 2025; and Saudi Arabia, Pakistan and Türkiye signed the Makkah Joint Defence Agreement on August 7, 2026. The Makkah agreement says an armed attack on any one of the three countries will be regarded as an attack on all three.So why have Pakistan, Turkey, or the US not joined the fighting against the Houthis?Why aren’t Pakistan and Türkiye fighting alongside Saudi Arabia?While the Makkah agreement is supposed to be a defence treaty, few details about its actual operational structure are available publicly. It does not delineate the escalation ladder, or what sort of response is expected from a member at which stage when another is facing attacks.Story continues below this adBoth Pakistan and Turkey have said that Saudi Arabia has not requested them to send combat forces to Yemen. Turkish officials have said their Parliament is yet to approve the defence treaty.Pakistan, of course, also has another mutual defence pact with Saudi Arabia. However, barring a few fighter jets it sent in April when Iran was attacking US military assets in the kingdom, Pakistan hasn’t intervened militarily. Nor has Saudi Arabia come to Pakistan’s aid against Afghanistan, with both countries prioritising their own immediate concerns.In the past few days, Pakistan has said it will extend all help to Saudi Arabia, but hasn’t given details. Recently, defence minister Khawaja Muhammad Asif told a Pakistani news channel that, “Under the trilateral agreement, if the territorial integrity of a country comes under threat, the agreement will be activated and the other two countries will proceed to protect it in fulfilment of their obligations.” But when asked specifically about military involvement against the Houthis, Asif said the government’s strategies couldn’t be made public at this stage.Both Pakistan and Turkey are using diplomatic channels to calm the fighting. Pakistan specially has asked Iran, the Houthis’ main benefactor, to rein in the militia.Story continues below this adWhy isn’t the US fighting the Houthis?US President Donald Trump has reportedly declined Saudi requests for direct military intervention against the Houthis.The US has participated in the Yemen conflict in the past. It reached an understanding with the Houthis in 2025, under which it stopped its bombing campaign in return for a Houthi commitment not to attack American vessels.That arrangement is still relevant. Right now, the Houthis are threatening only Saudi ships in the Red Sea, but they have the power to completely disrupt navigation in this crucial water body. With the world still reeling from the economic shock of the blocked Strait of Hormuz, the US would not want this. Also, US munitions are running low as the war with Iran grinds on. The Trump administration would not want to open another front in the Middle East when midterm elections are approaching and the Iran war is anyway unpopular.Also in Explained | Iran, US on brink of war again: For India, a lot to watch out forThen is the Iran factor. The Houthis have largely been trained and armed by Iran. If other countries were to enter active fighting on Saudi Arabia’s behalf, Iran and its allied militias might get behind the Houthis openly, adding another dimension to the US-Israel-Iran war and risking a much wider conflagration in the region.Story continues below this adWhy doesn’t Saudi Arabia simply fight the Houthis alone?Because Riyadh has already tried that. The Houthis are Zaidi Shias, and Yemen’s civil war began because they felt marginalised under the Sunni government. In 2014, they captured the capital, Sanaa.Saudi Arabia, a major Sunni power, intervened militarily in 2015. The rich Saudi Arabia has a modern, well-equipped military, but the Houthis survived years of pressure, while the war produced enormous humanitarian and political costs.A UN-mediated truce in 2022 significantly reduced the fighting, although it was never turned into a permanent settlement. The current escalation came because the Houthis want Saudi Arabia to remove its blockade of the territories they control.Today, the Houthis are far better trained and equipped, especially with missiles and drones. A direct confrontation, thus, could be prolonged and messy, with both economic and security costs for Saudi Arabia, at a time the Iran situation is anyway volatile and Riyadh would like to prioritise its growth ambitions.