Sir: An idea can be fought only with another superior idea. The Islamic State of Iraq and Syria (ISIS) is not merely a conglomeration of fanatical people/fighters but an idea of the caliphate. This caliphate represents military power on a territory in the interest of establishing Islamic rule, therefore it has huge attraction for the Muslims all over the world and is spreading through alliances/takeovers in other countries. Though the ISIS caliphate represents misinterpreted Islam and is attracting misguided Muslim youths from all over the world (which enabled ISIS to perpetrate cruelties and excesses on the gullible and helpless people including women, children, old people, etc) but it can be fought effectively by the US-led coalition forces only when a superior idea about human rights and justice to all is visibly there to defeat ISIS. HEM RAJ JAIN Bengaluru, India