A dispute between Iraq and Turkey has emerged as a dramatic geopolitical sideshow to the complicated military campaign to retake Mosul, Iraq’s second-largest city, from the Islamic State. President Recep Tayyip Erdogan of Turkey has insisted on a role in the battle for Mosul, trying to ramp up an involvement in Iraq that has already alarmed the Iraqi government. “We have a historical responsibility in the region,” Mr. Erdogan said in a recent speech, drawing on his country’s history of empire and defeat, from Ottoman rule of the Middle East to its loss in World War I. “If we want to be both at the table and in the field, there is a reason.” In response, the normally mild-mannered Iraqi prime minister, Haider al-Abadi, warned last week of a military confrontation between Turkey and Iraq. If Turkish forces intervene in Mosul, he said, they will not […]