Yemen’s Tehran-aligned Houthi movement has threatened to besiege a second key Middle East waterway as Iran launched drone attacks against US Navy vessels in the Strait of Hormuz over the weekend after a diplomatic effort to end the war appeared to collapse. A closure of the Bab el-Mandeb Strait, which connects the Red Sea to the Indian Ocean, would effectively sever Saudi Arabia’s only remaining oil export route. The kingdom has been shipping up to 7 million barrels of crude per day through the...