Beginning of US occupation of Pakistan

Post 9/11 US invaded Iraq and Afghanistan in a stated policy of pursuing the terrorists right into their hideouts (Afghanistan) and to find and destroy unconfirmed weapons of mass destruction (Iraq).

Why did US not invade Pakistan who has a declared stockpile of weapons of mass destruction and is also the birth place of Taliban - traditional recruiting academy for global jihadis.

When lotacracy was at its height and being actively promoted by General Musharraf and his crony establishment, I believed that reason for US hesitation in attacking Pakistan is due to US confidence in saleability of Pakistani politicians. If you can occupy by proxy then why waste expensive military hardware. In my darkest hours this is how I would have read the script for a very easy US occupation of Pakistan:

• a small contingent of US Marines (around 1000) are dropped by air into Islamabad to take control of the presidency/parliament etc. and Kahuta
• Richard Holbrook would land at Chaklala airbase as the US appointed Lord Protector of Pakistan
  
• overnight a group of like-minded politicians (read lotas) from Pakistan Muslim League and Pakistan Peoples Party would have formed forward blocs or a new political party named PML (Barrack Obama group)
• This new political party will convene a session of parliament to invite and accept American occupation of Pakistan under the doctrine of necessity. A necessary 18th constitutional amendment would ensure that Holbrook's accession to power is legal and constitutional.
  
• Political opinion in Pakistan would be divided with Jamat-e-Islami starting street protests and Maulana Fazl-ur-Rehman joining the newly formed interim government as Minister of Petroleum

Only unknown in this equation has always been the Pakistan Army who on top of being the guardian of geographical borders of Pakistan have also stated responsibility, rightly or wrongly, for protection of its ideological boundaries. How would Pakistan Army react to this script? In my view lack of an answer to this question has kept the US invasion and occupation of Pakistan to be nothing more than a hypothesis. One might not agree with the political ambitions of some of our generals but there has never been any doubt on their loyalty to the state of Pakistan. Same can not be said about a whole bunch of characters on our political scene.

Recent reports of US investment of $112.5 billion in building of a Marine House in the heart of Islamabad to host 1000 US Marines raises the question whether some variation of the script has already been written and is being put in place. What is the purpose of stationing 1000 US marines in Islamabad? If they are there for protecting American "interests" Surely Pakistan Army that has for quite sometime provided protection to friendly Arab capitals can protect any diplomatic "interests" in its own capital.

Given our general mistrust in capability of our political masters in assessing and planning for the long term I wouldn't be surprised that this has tacit approval from the current political masters. The unknown still is the level of agreement General Kiyani and army leadership have given to such a move. I fail to understand why you would let a sizeable contingent of worlds most sophisticated military with potentially aggressive designs to be stationed in your capital. Unlike Baghdad, Islamabad doesn't need a Green Zone.

I believe that an answer is due, General Kiyani!