ChanakyaM wrote: What casus belli do we need? POK is ours and so is the aksai chin. We do not need any other reason to take it back
This is a very childish and foolish way of looking at strategy, and no country in its right mind will start a major war "because we have a right to do it and we feel morally justified".
I'll address the Paki question in a moment, but first let's talk China. As things stand at this moment, starting a major war against China to retake Aksai Chin (A/C) is IMO simply out of the question, assuming a sane set of planners New Delhi. Things might have been different if the Chinese were still taking
panga with us now the way they have done many times in the past (salami slicing, building roads on our side of the LAC, etc.). Any of those actions, if conducted now, may well constitute a
casus belli (C/B) to at least start a shooting war in Tibet (not just A/C but also across the border from Himachal Pradesh, Sikkim, Arunachal Pradesh etc.). The object of the battle then would not necessarily be to capture the whole of A/C, but to seize and hold territory to be used as a bargaining chip in future negotiations.
Legal / moral reasons and justifications (which is what C/B is, in fancy Latin terminology)
matter a lot on the international stage. Any nation starting wars without them will soon become an international pariah, and India cannot afford to take that risk. It may appear to some that countries like US/Russia/China do that a lot, but in fact they don’t. Even they, wealthy/powerful as they are, are careful to provide some justification for military action. For example, IMO Russia was well justified in occupying and annexing Crimea (the C/B was NATO’s treachery in Ukraine) and in their military ops in Syria (the C/B was ISIS
chutiyapanti all over the middle east, aided and abetted by Turkey, Israel and the US). Likewise, IMO, Israel had a valid C/B to use its air force to bomb Hamas positions in Gaza, etc. You or I or anyone else may disagree with this or that C/B in any particular case, but the fact is that a substantial part of world opinion did, in fact, agree with them.
If we started a shooting war in either POK or A/C, and the war didn’t go well (e.g. lasted 2 weeks with no decisive outcome) and we had no halfway-reasonable C/B to offer the world, who the hell would side with India or bother doing business with us? Goodbye foreign investments, goodbye military cooperation etc. And we started it all for what reason?
World (to India): What the hell is going on? Why did you start this crazy war?
India (to world): Why do I need a special reason? This is my territory, that is reason enough. It has been under illegal occupation for 74 years, I put up with that patiently for all that time, but now I decided that enough was enough, so I decided to go to war.
World: WTF!! Why now? If it was okay for you (or at least tolerable) for 74 years, what changed?
And your suggested answer to this question would be…. ??
At least in the hypotheticals I presented earlier (China continuing its physical aggression), or Pakistan continuing its terrorism, our answer could be quite simple and reasonable:
“China (or Pak) has made clear by its actions that it will not live peacefully as our neighbour, it will continue its hostile actions threatening India’s national security or vital national interests, so our hand was forced. We had no choice”.
The world (or at least a reasonable percentage of it) would reluctantly accept that reasoning.