I do not think that there was ever any window of opportunity, nor that our cautious and generally peaceful leadership ever thought of such a military solution. If you examine the records carefully, except for the present set of ponces, nobody, ever, even during Vajpayee's strongest period, or during Indira Gandhi's military salience, thought of anything like India has faced. Not even on the covert level; let us get past the ever-present conviction even in balanced Pakistani minds of India's unilateral involvement in terrorist activity from the outset, and recall that on two separate occasions, the only effective intelligence agency that we had was asked not to engage with Pakistan. The second occasion lasted till three years ago; how anyone, forbidden to engage with specific entities, could do so in the Indian context of a bureaucracy unable to think, leave alone act, beyond their brief, is difficult to visualise.
Subvention of those opposed to Pakistani domination of parts of what is already Pakistan and accepted as such in all international fora, or tacit support to the extent of providing critics the ability to travel by providing them with alternative documents is an entirely different matter. These are actions taken by MEA, and are taken in the face of deep misgivings on the part of the professional cadre.
Strategic restraint was never an excuse for inaction; it was seen as an extension of some aspects of Indian political DNA. It is my personal regret that even the wisest and most broad-minded of my Pakistani interlocutors has seen this as an act of cowardice, more a case of 'I dare not' than one of 'I will not'. Even a cursory examination of the available assets, even more, the available opportunities, would show that a determined enemy could do enormous damage, perhaps even irreversible damage to an adversary other than the PRC. Please disregard the antics of the fanboys. We chose not to.