I count Kargil war a biggest blunder of Musshi BHai and Pak army (Recent past Years). It changed the world opinion against to Pakistan because of Stabbing in the back.
If I remember correctly then Even your closest friend "china", did not support to Pakistan and asked to pullout of forces to the pre-conflict positions. At the Time, Pakistani government was saying that those are not from Pakistan army and we have don't have control i. e Two Pakistani soldiers received the Nishan-e-Haider.
Then after 9/11, Everting got changed.