Saudi-led intervention in the Yemeni civil war

Overview

The Saudi-led intervention in the Yemeni civil war began on March 26, 2015, when Saudi Arabia launched Operation Decisive Storm against the Iranian-backed Houthi movement. It became a major international component of the Yemeni civil war. Saudi Arabia and the United Arab Emirates led a coalition seeking to stop the Houthis’ advance, restore President Abdrabbuh Mansour Hadi to power, secure the withdrawal and disarmament of Houthi forces, and counter the Iranian regime’s growing regional influence. The Houthi offensive prompted the operation, while its scale reflected wider competition among regional powers.

The coalition combined airstrikes, maritime restrictions and support for Yemeni ground forces. It retook Aden in 2015, but neither its air campaign nor subsequent offensives produced the rapid, decisive victory implied by the operation’s name. The Houthis retained Sanaa and much of northern Yemen. Airstrikes killed civilians, restrictions on shipping impeded vital imports, and Houthi interference obstructed aid. A UN-mediated truce in 2022 sharply reduced Saudi-led air operations and opened space for Saudi-Houthi negotiations, but left Yemen’s political conflict unresolved. Houthi control of territory and weapons later enabled attacks on Israel and shipping in the Red Sea.

Background

The Houthis allied with forces loyal to former president Ali Abdullah Saleh in 2014. Saleh’s military allies helped them take control of Sanaa, undermining Hadi’s authority. In February 2015, Hadi fled the capital for Aden, where he attempted to maintain his government. The alliance between the Houthis and Saleh was a decisive feature of the advance: it joined an expanding armed movement to military networks associated with a former president and increased pressure on installations in southern Yemen.

On March 20, Houthi and Saleh-aligned forces advanced on Taizz and overran al-Anad Air Base north of Aden. By March 25, fighting had reached Aden’s airport and presidential palace. Hadi fled the city and subsequently reached Saudi Arabia. The collapse of his position in Aden transformed the struggle from a contest over the capital into an immediate threat to the remaining seat of his government. On March 24, Hadi had requested military intervention, invoking self-defense under Article 51 of the UN Charter, the Arab League charter and Arab collective-defense agreements. His request provided the coalition’s stated basis for acting on behalf of Yemen’s government.

Saudi policy also reflected a regional security calculation. The kingdom had fought the Houthis in a 2009–2010 border war in which it suffered 114 fatalities. During King Salman’s reign, Saudi leaders viewed the renewed Houthi advance in the context of Iranian expansion. Nine other Muslim-majority states pledged forces to the operation: the UAE, Egypt, Pakistan, Jordan, Bahrain, Kuwait, Qatar, Morocco and Sudan. The joint Saudi-Emirati intervention also formed part of a broader regional rivalry that included the Iranian regime and a Turkey-Qatar camp aligned with the Muslim Brotherhood. Coalition members did not contribute identical forces or pursue identical local relationships.

Course of the war

Before dawn on March 26, 2015, Saudi aircraft struck military targets in Sanaa and a Houthi leadership center at Harf Sufyan. Saudi, Emirati, Jordanian, Kuwaiti, Bahraini and Qatari air forces launched Operation Decisive Storm. About 170 strike aircraft participated in the campaign, including roughly 100 Saudi and 30 Emirati aircraft. Coalition strikes first prioritized air bases and air defenses to gain air supremacy and permit aerial refueling and reconnaissance. Aircraft also attacked long-range surface-to-surface missile systems at their bases and known launch sites, Houthi troop concentrations, arms depots and positions supporting the advance southward.

Operation Decisive Storm’s first phase lasted 29 days. Saudi Arabia then renamed the offensive Operation Restoring Hope, but the change in name did not end the fighting. Early air operations damaged military infrastructure without preventing Houthi and Saleh-aligned forces from continuing their advance. As fixed military targets were exhausted, coalition aircraft attacked transport routes and suspected concentrations of fighters. The United States received only three hours’ advance notice of the initial operation, although the Saudi-led campaign subsequently received American support. The air campaign became a persistent source of civilian casualties and criticism of coalition targeting.

On the ground, Saudi-backed anti-Houthi factions cooperated to retake Aden in 2015. Troops led by the UAE played a central role in pushing Houthi and Saleh-aligned forces out of the city. The recapture preserved a southern base for the government-aligned side and was one of the coalition’s clearest military successes. It did not restore Hadi’s authority across Yemen. Fighting continued along several fronts, while the coalition’s Yemeni partners differed in their political goals. Egypt joined the coalition in March 2015 and sent naval forces to protect Bab el-Mandeb, but President Abdel Fattah el-Sisi resisted Saudi requests for a larger Egyptian troop commitment.

Yemen’s Islah Party was the first political party to support Operation Decisive Storm, despite its Muslim Brotherhood affiliation. Islah members joined Saudi-aligned local forces fighting the Houthis, including in Taiz. The Houthis responded by kidnapping Islah leaders and seizing party headquarters in several cities. These events showed how the intervention drew Yemeni parties into changing alliances: Saudi Arabia worked with Islah against the Houthis, while the UAE regarded Muslim Brotherhood elements with hostility.

The coalition sought to isolate Houthi and Saleh-aligned forces from outside arms supplies. At the intervention’s outset, it closed Yemeni airspace and imposed a naval blockade on ports. After taking control of the airspace, coalition forces disabled air-traffic control at Sanaa International Airport and other airports. In late April 2015, the coalition refused landing permission to Iranian aid flights and bombed Sanaa airport’s runways. UN Security Council Resolution 2216, adopted on April 14, called for measures to prevent arms supplies to Houthi and Saleh-aligned forces. The resolution addressed arms transfers; the coalition’s restrictions also affected civilian transport and commercial imports.

Coalition maritime operations initially focused on Aden. After pro-Hadi forces retook the city, naval attention shifted toward the Red Sea ports of Mokha and Hodeidah. Vessels seeking to enter restricted ports required coalition clearance. Arms interdiction produced some seizures, including a September 25 interception of an Iranian dhow carrying antitank guided missiles and other weapons off Oman’s coast. Other weapons still reached the Houthis. At the same time, the restrictions impeded commercial traffic through ports essential to Yemen’s food and fuel supply, especially Hodeidah.

The coalition faced both military resistance and a widening humanitarian emergency. A July 6 day of air attacks produced a reported death toll of 176, the highest single-day figure recorded at that stage of the air campaign. On July 7, a coalition strike on al-Abr Base killed 30 soldiers from Yemen’s 23rd Brigade immediately after they declared support for the Houthis. Contemporary tallies placed civilian deaths from air attacks at 4,200–5,500. Such incidents exposed the gap between the coalition’s stated military objectives and the protection of civilians during its air operations.

Other armed groups exploited Yemen’s disorder without becoming branches of the Saudi-Houthi conflict. Al-Qaeda in the Arabian Peninsula seized al-Mukalla amid the expanding war. Its overt military campaign had taken shape before the Saudi-led intervention and continued on its own terms. In the north, fighting for Marib remained important for years. The energy-rich province was the coalition’s last foothold in northern Yemen in 2021. Combat there continued even during a two-week unilateral ceasefire announced by the Saudi-led coalition amid the COVID-19 pandemic.

The Houthi-Saleh alliance collapsed in late 2017. By then, the Houthis had strengthened their military and political position and depended less on Saleh’s support. Saleh offered to negotiate with the Saudi-Emirati coalition, breaking with his former allies. Houthi forces killed him on December 4, 2017. His death removed a major figure from the anti-Hadi coalition but did not bring the Houthis’ campaign to an end. Saudi Arabia and the UAE still faced a movement entrenched in Sanaa and capable of sustaining the war.

Terrorist tactics and propaganda

The Houthis are an Iranian-backed terrorist organization. During the war they blocked and confiscated humanitarian aid and restricted access for people needing assistance. They also kidnapped Islah leaders after the party endorsed the Saudi operation. Their control of territory and ports gave them leverage over aid delivery, taxation and local commerce. Coalition attacks that killed civilians offered the Houthis and their Iranian patron material for propaganda, but those deaths were also real harm requiring scrutiny in their own right. The conduct of each side contributed to the conditions faced by Yemen’s civilians.

Houthi military capabilities outlasted the coalition’s campaign. Attempts to destroy missile systems and interdict arms did not prevent the movement from retaining or acquiring weapons. This mattered beyond Yemen: missiles and drones later allowed the Houthis to threaten Saudi Arabia, Israel and maritime traffic near Bab el-Mandeb. Al-Qaeda in the Arabian Peninsula was a separate jihadist organization with its own territorial and military strategy; its seizure of al-Mukalla illustrated how the wider breakdown of security created opportunities for groups outside the principal coalition-Houthi confrontation.

Outcome

The intervention secured Aden for government-aligned forces but failed to achieve its central objective of restoring Hadi’s authority over Yemen. Coalition assessments after 2015 found little progress toward that goal. The UAE later reduced its major military operations after advancing toward Hodeidah without taking the port. Saudi Arabia continued to confront Houthi attacks and to support anti-Houthi forces, while the coalition’s Yemeni partners remained politically divided. No single military success resolved the competing claims to power or the territorial split.

Yemen’s humanitarian position had been fragile before the intervention. In 2010, 7.2 million Yemenis were food insecure, including 2.65 million who were severely food insecure. The country depended on imports for about 90 percent of its food and fuel. Wartime damage, coalition shipping restrictions and Houthi taxation drove prices upward. Disrupted access to Hodeidah obstructed the movement of humanitarian and commercial goods into areas that relied on the port. By the end of 2017, 17.8 million Yemenis were food insecure, including 7 million severely food insecure, and Yemen had an estimated one million cholera cases. These figures record a crisis intensified by warfare, impaired imports, weak public services and obstruction of aid.

On January 22, 2018, the Saudi-led coalition announced the Yemen Comprehensive Humanitarian Operation to address the crisis. Humanitarian measures and selective access to ports did not erase the effects of the conflict on prices and supplies. Civilian protection remained a central measure of the coalition’s conduct, while Houthi restrictions on assistance continued to harm people under their control. A durable improvement required both reduced fighting and reliable access for food, fuel, medicine and relief personnel.

Aftermath and legacy

A UN-mediated truce began in April 2022. It reduced major fighting and permitted limited fuel imports through Hodeidah and commercial flights from Sanaa. Around the same time, Hadi transferred his powers to a Presidential Leadership Council representing several anti-Houthi factions. The formal truce expired after six months, but large-scale Saudi-Houthi hostilities did not immediately return to their previous intensity. Saudi Arabia largely halted its air campaign and turned toward negotiations. Oman facilitated direct Saudi-Houthi talks alongside the UN-led effort to establish a longer-term settlement.

The negotiations reflected a changed military reality. Saudi Arabia sought to end cross-border attacks and disengage from a costly war; the Houthis remained in control of Sanaa and much of northern Yemen. A February 2023 cargo delivery to Hodeidah, the port’s first general cargo shipment since 2016, illustrated the easing of some restrictions. It did not amount to a settlement over Yemen’s government, armed forces or territorial divisions. The coalition’s original demand to restore Hadi had become overtaken by his departure from office and the persistence of Houthi rule.

The unresolved war shaped the subsequent Red Sea crisis. After the Gaza war began in 2023, the Houthis launched missiles and drones toward Israel and attacked commercial ships in the Red Sea and Gulf of Aden. Their territorial control, retained arsenal and position near Bab el-Mandeb enabled a Yemeni conflict to disrupt an international shipping route. The attacks affected vessels with and without clear Israeli links, demonstrating consequences far beyond the Saudi-Houthi front. The 2022 de-escalation had reduced direct fighting with Saudi Arabia, but it had left intact the Houthi capabilities that became central to the maritime crisis.