Strategically speaking, that is. It is important to think this question through.
For one, there’s hardly anybody disputing that the Lashkar-e-Tayebba was behind the attack. Pakistan wants evidence, but doesn’t deny the LeT could be it.
Parvez Hoodbhoy says in an interview:
LeT, one of the largest militant groups in Pakistan, was established over 15 years ago. It was supported by the Pakistani military and the ISI because it focussed upon fighting Indian rule in Muslim Kashmir. Today it is one of the very few extremist groups left that do not attack the military and the ISI; Continue reading Looking Kabul, talking Rawalpindi?