For months, the front lines of Yemen's civil war have been fairly stagnant. But on Jan. 7, Yemeni troops backed by Emirati forces began to advance on the city of Dhubab, near the Bab el-Mandeb strait. The stated objective of the operation, known as "Golden Arrow," is to secure Yemen's western coastline in Taiz province in the hope of blocking any further arms deliveries to Houthi rebels and supporters of former President Ali Abdullah Saleh. However, the offensive will also greatly reduce the risk of anti-ship missile attacks against vessels transiting the waters off Yemen's coast....