A conflict that has simmered in Yemen for years has flared in recent weeks, with consequences that could reach far beyond the Middle East. The Houthi rebels have seized nearly all of Yemen’s Red Sea coastline, giving the Iran-aligned militant group control of the Bab al-Mandab Strait, a key chokepoint for global trade. The Houthis have also intensified attacks on energy facilities in Saudi Arabia, the group’s foe and the world’s biggest oil exporter. Riyadh has been forced to temporarily shut down a crucial oil pipeline after…