The last three weeks have brought the world's biggest oil-producing region back into the headlines. From a crisis in the Gulf Cooperation Council (GCC) to the political aftermath of a terrorist attack in Tehran, recent developments have renewed concerns that turmoil in the Middle East could cause havoc in the international oil market. Despite the heightened commotion, however, these concerns are misplaced. More than regional tension, the Islamic State's activity in southern Iraq -- and perhaps southern Iran -- presents a serious threat to energy production....