1. It would be prudent to believe that there was a failure in intelligence with respect to the current scenario as the agencies did not connect the dots/analyze that such a situation would arise
2. If things go south, US might provide specific intelligence that can help us but this might come at a price
3. We did not develop our infrastructure at the border, this is a collective failure of all governments
4. Even though we patrolled till F8 our claim was not strong, the Chinese have built roads & other structures there. This has been happening since the last 25 years, we should have objected to this
5. 2.5 front war (full fledged) might be unlikely but cannot be ruled out as well. USA might try to prevent this as things could get really bad as in mushroom cloud level bad, since India will do/use whatever weapons it has to maintain territorial integrity
6. China believes that it has reached a state wherein it can wage, control and possibly win a war with India. A win, for China, would be an announcement to the world that it is ready to take on the USA & that all smaller Asian countries need to fall in place
7. China believes that India (a nuclear power) would be shown its place & that it should not get too uppity