Bangladesh, Sept. 13 -- The latest developments in Yemen should not be dismissed as another episode in the country's seemingly endless civil war. The reported Houthi advances around the port of Mokha and several strategically important islands in the southern Red Sea, if consolidated, would represent a significant shift in the regional balance of power. More importantly, they would underline a reality that policymakers have repeatedly underestimated: Yemen is not merely a domestic battlefield. It sits astride one of the world's most important maritime chokepoints.

The Bab Al-Mandab Strait connects the Red Sea with the Gulf of Aden and provides a crucial passage for international shipping. Any armed group capable of threatening this wate...