It is difficult to view Saudi Arabia’s relentless war of attrition in Yemen as anything other than a destructive failure. The military intervention that began one year ago has killed an estimated 6,400 people, half of them civilians, injured 30,000 more and displaced 2.5 million, according to the UN. Eighty per cent of the population, about 20 million people, are now in need of some form of aid. Saudi Arabia has paid a high political and diplomatic price for its Yemeni misadventure, with scant return so far. Its actions have turned the spotlight on its lamentable human rights record, notably its recent execution of Sheikh Nimr al-Nimr, a leading Shia cleric.