It's also no secret the group has received staggering sums from sympathetic Sunni Arab neighbors, both wealthy private donors and, reportedly, elements of some legitimate governments as well. The sheer enormity of the group (with more than 40,000 fighters covering 30,000 square miles of Iraqi and Syrian territory) and its span of control, which includes millions of civilians, require billions of dollars a year to maintain. The next step, then, is to put a rapid stop to the movement's economic viability. Middle Eastern governments that have a stake in the stability of the region, and which are themselves dependent upon western governments for economic and political survival, should be put on notice that any complicity in the movement's funding, either through illicit means or under the guise of "humanitarian aid," will be considered hostile acts. Actions to stem the flow of these kinds of funds must be prioritized, and carefully coordinated with, allies in the region.