Saudi Arabia is confronting a rapidly worsening security and economic crisis as Houthi rebels expand their reach along the Red Sea, attacks blamed on Iran-backed Iraqi militias disrupt a major oil pipeline and Iran continues to impede shipping through the Strait of Hormuz. The developments threaten Saudi energy exports and the kingdom’s effort to attract investment and build a more integrated regional economy. They also come as Saudi leaders question how much support they can expect from the United States, their most important security partner. Over the past two days, Houthi forces seized the Yemeni port city of Mokha and a Red Sea island from forces aligned with Saudi Arabia’s government in Yemen. The gains could strengthen the rebels’ ability to threaten shipping near the Bab el-Mandeb, a strategic passage connecting the Red Sea with the Gulf of Aden and the Indian Ocean. The Houthis resumed large-scale attacks this summer after a four-year lull and declared a blockade of Saudi shipping in July. Their campaign has contributed to a sharp decline in Saudi oil shipments to Asia, according to figures compiled by Kpler, a global trade monitor. Exports fell from about 3.4 million barrels per day in June to 128,000 in August, before recovering to roughly 700,000 this month. Saudi Arabia said Friday that it had halted operations on a pipeline carrying oil from fields in the east to the Red Sea coast after drone attacks originating in Iraq. Regional officials have said the Houthis helped Iraqi militias conduct attacks, though the claims could not be independently verified. The pipeline had provided Saudi Arabia with an alternative to routes affected by conflict around Hormuz. Oil sent across the peninsula can reach European markets through Egypt’s SUMED pipeline and the Suez Canal, or travel toward Asia through the Bab el-Mandeb. A Saudi official who was not authorized to speak publicly said the kingdom would defend itself and coordinate with partners, including the United States, to protect freedom of navigation in the Red Sea. The Saudi government did not otherwise respond to requests for comment. Michael Ratney, a former U.S. ambassador to Saudi Arabia, described the situation as “incredibly frustrating” for a kingdom that had sought to avoid another war in Yemen. “This is a war they had never asked for,” he said, adding that the worst outcomes Riyadh feared have begun to materialize. Saudi Arabia launched a military campaign against the Houthis in 2015, but the intervention failed to defeat the group. The war killed an estimated 150,000 people and helped push Yemen toward famine before a ceasefire in 2022. The latest Houthi advances put Crown Prince Mohammed bin Salman’s economic agenda under renewed strain. The de facto Saudi ruler has spent years pursuing social and economic changes intended to transform the kingdom into a global business center, while seeking greater regional stability. Neil Quilliam, a Middle East expert at Chatham House, said the rebel gains were forcing Riyadh to consider options that all carry serious drawbacks. A stronger military campaign could prolong the Yemen war and invite intensified attacks on Saudi energy infrastructure. Diplomacy with the Houthis or Iran could reduce immediate tensions but might allow the rebels to consolidate power. Sherwan Hindreen Ali of the conflict-monitoring group ACLED said the Houthis now possess more advanced weapons than they did during the earlier Saudi intervention. Saudi Arabia may also have fewer interceptor missiles available after the wider U.S.-Iran conflict, making a renewed campaign more dangerous for the kingdom. The United States has previously relied on military action against the Houthis, including an air campaign last year after attacks on Red Sea shipping connected to the war in Gaza. But U.S. forces are now concentrated around Hormuz, where they are blockading Iran and attempting to protect commercial vessels. The fighting has strained American military resources and reduced stocks of sophisticated missile interceptors. President Donald Trump said Saturday that Iran was “probably” responsible for the pipeline attack. He also said of a recent conversation with Mohammed bin Salman, “He’s a good friend of mine, and I can just say everything’s going to work out fine and dandy.” The White House has not said whether it will intervene in Yemen. Trump has indicated that political concerns are shaping his approach to the broader conflict, telling Fox News that he might avoid increasing military pressure “because of the election.” The war has become unpopular in the United States after Trump campaigned on avoiding new Middle East conflicts, and a new Yemen operation could create additional problems for Republicans in closely contested congressional races. Ratney said Saudi Arabia would struggle to protect its interests without sustained U.S. backing. “My understanding at this point is the White House is not enthusiastic about getting involved,” he said. For Riyadh, the immediate challenge is to keep trade routes and energy infrastructure operating without returning to an open-ended ground war or provoking a wider confrontation with Iran. Quilliam said the kingdom’s available choices have “significant costs and uncertain outcomes,” leaving Saudi leaders to balance economic ambitions against threats that are increasingly difficult to contain.