Two - thirds of Americans say ' ` ` major threat '' to U.S. Government officials have estimated numbers of Americans fighting for ISIL , says Peter Bergen . Two-thirds of those surveyed in a recent Pew Research poll said they consider the Islamic State in Iraq and Syria to be a `` major threat '' to this country . Claims that over 100 U.S. citizens fighting with ISIS are probably overestimate . This example suggests those fighting in Syria wo n't be U.S. citizens , Bergen says .
Two - thirds of Americans say ' ` ` major threat '' to U.S. Government officials have estimated numbers of Americans fighting for ISIL , says Peter Bergen . Claims that over 100 U.S. citizens fighting with ISIS are probably overestimate . This example suggests those fighting in Syria wo n't be U.S. citizens , Bergen says .