Ok u put some good points,now is my turn
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Scenario 1- its pakistan job-not directly but indirectly. Bcz directly involving will make their case more worsen..but indirect involvmenta like providing weapons, cash, support,data,training is much easier and its hard to proof anything at the end..
Scenario 2-its indian gov job- to kill some soldiers and gain the acceptence of indians to crush kashmiries terrorists as there are many rats here who on the name of secularism can sell there country...but finally easier to say than doing..bcz this kind of things will make ur own army ur enemy and u can thing what will happen thereafter..
Scenario3- locals militants did it- just explain how a bunch of 4-5 peoples get that much accurate gps positions, ammunitions, weapons, strategy, and training that they managed to enter a well secured and fortified army base..no one in world will believe that its the work of just 4-5 peoples..
So now which scenario suits u better ..answer like a 3rd party..
Coming to india china war- china had their chances earlier but not now..bcz in the end two civiliztions will become eradicted from the world map..so nobody can thrash anyone..they understand it better then u ,thats y they keep maintaing peace on border and prefer other ways to settle disputes..