Whatever the current Pakistani Defence Minister is saying today was said by General Ayub Khan in 1965, by Gen Yahya Khan in 1971 and Gen. Musharraf in 1999. Each time they lost the battles and the war.
A stern message was delivered by U.S. National Security Advisor, sent in an urgent mode, by President Obama to tell the Pakistani General's to cool it on nuclear rhetoric. Although if you ask a Pakistani diplomat in Rawalpindi, and he will say that Ms. Rice came for a hand shake and get acquainted. It seems that U.S., NSA did not meet relatively unimportant Pakistani Defence Minister, but she saw the COAS and the Prime Minister.
That "unacceptable damage" on India has a cost to Pakistan also I.e. It will cease to exist on the map of this earth. Eight times larger India will survive, but Pakistan and Muslim world in South Asia will be wiped out for ever. After that there will be no Kashmir dispute. Pakistan geography is such that a fewer larger bombs can destroy it beyond comprehension than well distributed population centres of India. Moreover smaller tactical battlefield nuclear bombs which Pakistan is boasting, have a limited destructive potential. Imagine 3 mega ton Indian bomb over Rawalpindi or Karachi or Sargoda or Multan or Sialkote will not only destroy these cities but will render all the surrounding areas with in 100 miles area useless for ever. All it will take is for Pakistan to start a nuclear war with one tactical nuclear strike on forward Indian troops.
But before it comes to that U.S. Will intervene. They will not interfere if a convention fight is taking place. They understand that this conventional fight is not unusual. Muslim world is full of these episode. Every time after this fight Muslim after they loose, settle down to rebuild and restart it again like in 1948, 1965, 1971 & 1999.
Point here is that, threats aside, Pakistan does not have guts to face complete destruction. They already have lost world's sympathy by becoming terror activities headquarter, they do not wish to loose any more. With US, NSA visit, if there was any doubt left in Pakistani mind, it has been removed.