On both sides of the Atlantic, authorities are grappling with what to do with people linked to Islamic State (ISIS) returning home from the war in Syria. President Donald Trump has said Hoda Muthana, who left the U.S. to become a propagandist for ISIS, “is not a U.S. citizen and will not be admitted into the United States“, while Shamima Begum, who left London four years ago with two friends to join up with ISIS in Syria, has been stripped of her U.K.