India does not have the option of blithely invading another country like Israel or the US; nor, if it could, would it be a very productive policy. The war against the sponsors of terrorism has to be a covert one; I hope that India is preparing to wage a covert war.
The world's problem is to be manage the terminal decline of an ideology that will not go quietly into the night. I do not rule out Islam producing something like puritan Christianity or some other productive ideology. But Islamdom is in the grip of a nihilistic ideology that can produce nothing. The main problem is to keep that sinking ship from drowning the rest of us as well. Apart from being a prime source of terrorism, the Islamic world is saved from irrelevance only by two facts. One is of chance, that they sit atop massive oil reserves in a world that has a petroleum-based economy. The second is one of negligence and foolishness of the great powers, in that an Islamic country has nuclear weapons.
Indians have a phobia about Islam, because of the last many hundred years of history. The key thing to remember is that military power rests on a basis of economic power. In the medieval world, the economic power of Islamdom rested on its control of trade routes. In that world, control of production meant control of the serfs. This too, Islamdom had. India could never reach equilibrium with the Muslim invaders, because of the great external power of Islamdom that would constantly reinvade. Once the Europeans had broken the Islamic monopoly on trade, by opening up sea routes, the decline of Islamdom as then constituted was almost inevitable.
Today, economic and military power rest on the mastery of technology, and in innovation; and the current ideology of Islam utterly stifles and deadens these in its societies. As I wrote above, without the petroleum and the bomb, people would be paying less attention to them than they do to sub-Saharan Africa. If the world can manage a transition to a post-petroleum economy, a transition also forced upon us for ecological reasons, then only one reason Islamdom would have any relevance is its ability to produce nuclear terror.
Yes, it will be a great tragedy if Islamists overrun Europe. However, in the long run, it will not change any balance of power, because Islamists cannot run Europe at its current level of sophistication. They will be even less successful than the Soviets. There will be great human misery, but it will not be the end of the world.
Finally, the world makes a big mistake in taking India-Pakistan issues as some local problem, and making equal-equal between the two sides. To me it is fairly clear that there is simple thread from the ideology behind the formation of Pakistan to 9/11 and beyond. It need not have happened that way, of course, e.g., if the superpowers had not made Afghanistan into a battleground of the Cold War, and in the process, overlooked Pakistani nuclear development. But instead of holding Pakistan together, the world should be engaged in dismantling it and limiting the power of its constituent parts. The bailing out of the Pakistani economy and rearming Pakistan as the American administration intends to do - the matter is currently in Congress - will hasten rather than delay or cancel the day of a JDAM (Jihadi Detonated Atomic Munition).