Why Pakistani Establishment Planned the 26/11 Mumbai Attacks?

A very interesting and credible argument from Najam Sethi on why 26/11 was planned by the elements in Pakistani Establishment at that time.  Why not earlier, why at that time only?  The Mumbai Attacks in 26/11 brought the two nations back into a war like situation and any work that Asif Ali Zardari had done for peace was put on backburner.