There is something particularly concerning about the "masked, sociopathic murderers" who fight for the Islamic State in Iraq and the Levant (ISIS), writes former state department official Andrew G Doran for the National Review. Some of them, he says, are Western citizens who have travelled to Syria to fight President Bashar Assad's government - and have passports or other immigration paperwork that would allow them to return to their home countries whenever they want. In fact, he says, citing the Daily Beast's Greg Sargent, perhaps a dozen are already in the US.