(CNN) – When the extremist group the Islamic State of Iraq and Syria (ISIS) abducts boys from Friday prayers at mosques or indoctrinates children as young as 10 to become fighters or suicide bombers, there is little the United States can do. But when recipients of U.S. military aid recruit children into their forces as soldiers, the United States has a lot of leverage. It is disappointing that the Obama administration has been reluctant to use it.