“Degradation of ISIS is not the end goal,” Secretary of State Rex Tillerson said last week. In what appeared to be a criticism of the Obama White House’s ineffective campaign against the Islamic State, the Trump administration’s top diplomat insisted, “We must defeat ISIS.” At a two-day summit bringing together officials from the 68 countries and international organizations that form the anti-ISIS coalition, Tillerson said that “defeating ISIS is the United States’ number one goal in the region.”

The Obama administration failed in its efforts to defeat ISIS mainly because it never took on the Shiite expansionism—emanating from Tehran and spreading through the central government in Baghdad to Damascus and Beirut—that has fueled Sunni extremism. Given a choice between the depredations of the Islamic State and those of the Shiite militias backed by Iran, Sunnis caught in the middle have typically chosen to endure the former rather than risk the latter.