To Hurt ISIS, Squeeze the Cash Flow

ISIS has set itself apart from other terrorist groups not only by its barbarity but by its dream of establishing an Islamic caliphate. It employs an estimated 30,000 fighters, including 19,000 from 90 foreign countries, who are reportedly paid $350 to $500 a month. The total monthly bill is $10 million. The group has also sought to bolster its appeal by providing public services, including electricity, to the people under its control. That, too, costs money.