President Donald Trump's rejection of Saudi Crown Prince Mohammed bin Salman's appeals to launch strikes against the Houthis on Thursday has dramatically highlighted the kingdom's growing vulnerability — and isolation — in the face of a renewed Houthi campaign for control of the Bab al-Mandeb Strait. The crown prince telephoned Trump twice and was rebuffed both times, according to Axios, which broke the story.The news, confirmed to Al-Monitor by a senior official based in the Gulf, came as the Iran-backed militant group reached the key island of Perim on Friday, at the narrowest point of Bab el-Mandeb. It followed Thursday's capture by the group of the strategic Red Sea port of Mokha from Saudi-backed pro-government forces, who failed to stem the Houthi advance despite sustained Saudi air support. The price of Brent crude rose to more than $105 a barrel, its highest price since July, following Mokha's fall.Trump's reaction should not have come as a surprise, several regional officials speaking on background told Al-Monitor. American officials have said the administration has no plans to engage in direct military operations against the Houthis even as dozens of American military advisers remain on the ground in Saudi Arabia and concern mounts over the cascading effects of Houthi gains on the broader Iran conflict. CENTCOM head Adm. Brad Cooper traveled to Saudi Arabia on Thursday for what are being described as urgent coordination talks. But there is little indication that Washington will alter its stance, the sources said.America has had no appetite for conflict with the Houthis since reaching an Oman-mediated deal with the group in May last year. The Trump administration agreed to stop bombing Houthi targets in Yemen in return for a Houthi pledge to stop attacking American vessels in Bab el-Mandeb and the Red Sea. "The understanding was that the Saudis would contain the Houthi threat on their own," one of the sources briefing Al-Monitor said. But the start of the Iran conflict in February upended those plans.With America's focus locked on Hormuz and its military arsenal stretched ever thinner, Riyadh has had to enlist new allies to contain the Houthis. The idea was to establish what it hoped would be a deterrent shield of sorts — first through a Red Sea maritime pact on July 31, as first reported by Al-Monitor, then through the defense pact signed in Mecca on Aug. 7 with regional heavyweights Turkey and Pakistan.Pakistan and Turkey have both said the terms of the agreement call on all members to come to the defense of the others in the event of an attack. The dizzying developments in Yemen are putting the bold assertions made by the Turkish and Pakistani foreign ministers to their first real test. Pakistan has already said it has no plans to join the air campaign against the Houthis. Turkey has said nothing beyond calling for an end to the hostilities. Namik Tan is a former Turkish ambassador to Washington and a lawmaker for the main opposition party. "The Mecca pact is for now no more than a memorandum of understanding. There is no known text. Nothing has been brought before parliament. Nobody really knows what it amounts to," he said in an interview with Al-Monitor.In any case, neither Pakistan nor Turkey has an immediate and vital stake in Yemen, whereas for Saudi Arabia keeping Bab al-Mandeb open "has become a matter of economic survival," one official said. "And the fact that MBS has asked Trump to take the lead shows that the Mecca pact was never seen as a substitute for America to begin with," the official added, referring to the crown prince by his initials. "MBS believed he could bring Trump around, that the Americans would take a lead role, because you cannot divorce what is happening in the Bab al-Mandeb and the Red Sea from what is happening in the Strait of Hormuz."Dire straitsSaudi Arabia, OPEC's biggest producer, has had to reroute most of its oil through the Red Sea port of Yanbu since Iran closed the Strait of Hormuz, loading it onto tankers that transit the Bab al-Mandeb Strait. Since July, however, the Houthis have declared a blockade on all Saudi ships over alleged restrictions imposed by Riyadh on Houthi-controlled Yemeni ports and airports. The group says it poses no threat to international vessels but will continue to target those from Saudi Arabia.The Houthis' tightening grip on the Red Sea chokepoint is the biggest setback for Saudi Arabia and Yemen's internationally recognized Presidential Leadership Council since the Yemen conflict began in 2014. A UN-brokered truce in April 2022 marked the start of a fragile peace that now lies in tatters. "What the Saudis wanted was for the Americans and the Mecca pact to keep the Houthis well away from the Red Sea shorelines," one of the sources said.Iran is the ultimate beneficiary of Houthi gains, which have increased Tehran's leverage to extract further concessions of its own. Tehran's strategy since the United States and Israel ignited the war in February has been to inflict as much pain as possible on the Gulf states, both directly and through its various proxies, on the calculation that this would in turn push those states to pressure Trump into ending the war. That has not happened.Trump has declared that the memorandum of understanding he signed with Iran on June 17 is no longer valid and has ordered fresh attacks on Iran. There is little prospect of his position shifting before the midterm elections in November, amid bipartisan accusations that the memorandum amounted to a capitulation to the Iranian regime. The Gulf states are left scrambling to reach backroom deals with Tehran to stop the attacks against them and allow them to export their oil.Back to the tableGulf foreign ministers are due to meet their Iranian counterpart, Abbas Araghchi, in Oman on Monday, in a bid to secure an interim deal for managing shipping through Hormuz, according to the Financial Times. Should the bid fail, Saudi Arabia will again face a double blockade and therefore be forced to bargain once more with the Houthis."They will need to buy their way out of this crisis, as they did back in 2022, and that is what the Houthis are banking on," one of the sources said.In the medium term, however, such a deal would cement the weakened position of the Saudi-backed government forces and eventually trigger further conflict, the officials predicted. "It was precisely because the Saudis agreed to bankroll the Houthi administration in exchange for a ceasefire that they were able to build up to this moment," Amr Al Bidh, a member of the UAE-backed South Yemen Transitional Council, said in an interview with Al-Monitor. Part of the Presidential Leadership Council, the group controlled swathes of southern Yemen. But in 2025 it launched a major offensive in the south, calling for a two-state solution to the Yemeni civil conflict with the support of the UAE.In January this year, backed by Saudi air power, government forces launched a counter offensive, retaking Hadramawt and al-Mahrah as well as the port city of Aden. Emirati influence in Yemen was declared over as a result, and the ensuing vacuum facilitated the Houthi offensive, Bidh asserted."We have empirical evidence that over the last eight or nine years, the Emiratis were more effective militarily than the Saudis in Yemen," one of the diplomatic sources based in the region concurred. The Emiratis were part of the Saudi-led coalition until they exited the Yemen conflict in 2019 as the death toll among their forces began to rise, sowing the seeds of division between the two Gulf powers.However much satisfaction the Emiratis may be deriving from the Saudis' current predicament, Houthi control of Bab al-Mandeb works against their interests, too. The UAE has critical military and economic footholds in the Red Sea, notably in Somaliland, Djibouti and Eritrea. A key objective was to establish connectivity between those assets and the port of Jebel Ali in Dubai, the crown jewel of the UAE's global trade infrastructure. "That is why the UAE entered the Yemen conflict to begin with," one of the sources observed. "And that is why they too may be forced to cut future deals with the Houthis."