The Houthi advance to the Bab al-Mandab strait in mid-September has rewritten the military calculus in Yemen. The Iran-aligned group routed the UAE-backed National Resistance Forces led by Tareq Saleh, seized a chokepoint on Saudi oil exports, and is now pressing on Taiz with daily rotating attacks. The UN-recognised government has declared a general mobilisation — an admission that existing forces cannot hold the line. Riyadh created this vulnerability. In January, Saudi Arabia attacked and defeated the Southern Transitional Council, the UAE's principal ally in Yemen, in a bid to prevent southern secession. The UAE effectively withdrew from the conflict. The Giant Brigades — southern, UAE-trained, and among the best-equipped ground forces in the theatre — were sidelined. The force Riyadh dismantled is now the force it needs. The diplomatic scramble is visible across multiple capitals. An Abu Dhabi meeting on Sunday brought Netanyahu, Sheikh Mohammed bin Zayed, and Saudi representatives to the same table. Netanyahu offered Israeli help against the Houthis — an offer Riyadh almost certainly cannot accept publicly. A follow-up meeting in Riyadh on Tuesday between the Saudi defence minister, Prince Khalid bin Salman, and UAE vice-president Sheikh Mansour bin Zayed tested whether reconciliation is possible. The White House is privately pushing both sides to unify command and reintegrate the Giant Brigades. The structural problem is the southern question. Former foreign minister Khaled Alyemany, an STC supporter, told the Guardian that southerners will not fight to retake Sana'a for a government based in exile in Riyadh unless independence is on the table. The STC has urged the Giant Brigades to resist merging with government forces. Saudi Arabia has always opposed southern secession because a divided Yemen could entrench Houthi rule along its border. That logic now collides with the reality that the anti-Houthi coalition cannot function without the very separatists Riyadh marginalised. The Houthis, meanwhile, are negotiating from strength. As April Longley Alley of the Washington Institute told the International Crisis Group, 'The Houthis are demanding a victor's peace.' They learned from the Iran war that Saudi Arabia under pressure seeks de-escalation. The Houthis claim they are not blocking general commercial shipping through the strait — only Saudi-linked vessels — and published figures showing normal commercial flow. Their framing of the UN-recognised government as a Saudi colonial instrument resonates precisely because the government derives its legitimacy from Riyadh, not from any governed population. The human toll continues to mount. The WHO reports 838 killed and 3,643 injured from the escalation between August 2025 and late September 2026. Taiz, already one of the most besieged cities in the war, faces a new wave of attrition. The proposed use of Israeli intelligence and private security firms — something the UAE has deployed before in Yemen, 'sometimes to brutal effect' — adds another layer of escalation risk. The core dynamic is an extractive loop: Saudi Arabia destroyed its coalition partner's proxy, lost its buffer against the Houthis, and now must either reverse its own policy, accept Israeli involvement it cannot publicly acknowledge, or watch the Houthis consolidate control of a critical maritime chokepoint. Every option costs Riyadh sovereignty, credibility, or both. The civilians of Taiz and southern Yemen, as always, absorb the consequences of decisions made in Riyadh, Abu Dhabi, Tehran, and Washington.