pLast week, French security officials announced they had foiled what they called an "imminent" terrorist plot on the French Riviera. The main suspect was a 23-year-old French citizen, a radical Islamist who had just returned from Syria. There, he had fought in the so-called jihad, or holy war, against both President Bashar al-Assad's regime and rival rebel factions. The worry is that these seasoned fighters will return to France to carry out terrorist attacks.