US efforts to improve Saudi targeting, mentioned in a recent post, have not panned out. The US military effectiveness is about the same as when we train and equip Iraq freedom fighters. The difference is the Saudis can’t defect to ISIS, you can’t have a one sided coin.
http://news.antiwar.com/2017/12/31/saudi-warplanes-attack-crowded-restaurant-at-northern-yemen-port/

