At the slightest hint of normalisation of relations with India, every Pakistani government is accused of selling out on Kashmir. Yet, as the 1998 elections showed, a political party that stood for better relations with India won a record majority in parliament.
There is a Kashmir battle fought within Pakistan that is perhaps as intense as the militants' fight in Indian Kashmir and certainly much more vicious than the Pakistani diplomats' harangue of their Indian counterparts at the UN. This is the one fought by Pakistani politicians in an attempt to outdo one another in proving their empathy for the Kashmir cause.
If India claims that Kashmir is an "integral part" of its territory, Pakistan too can claim that Kashmir is an integral part of its domestic agenda. Politicians feel that they can win over the common citizen by appearing to champion the Kashmir cause. The opposition of the day makes full use of it to destabilise or at least embarrass the sitting government in Islamabad. And the government, for its part, has to appear to be doing something on Kashmir and uses the official media to portray its 'achievements' on the issue. All of which only serves to play into the hands of hawkish elements in the establishment and, in effect, makes it almost impossible to solve the Kashmir issue through negotiations.
Pakistan has felt the need to invoke Kashmir to garner public support right from the beginning when it supported the militia push to capture Kashmir in 1947. But after the 1947-48 war with India, the Kashmir issue remained in cold storage for nearly 20 years, at least on the domestic front. That is until Zulfikar Ali Bhutto, the charismatic foreign minister of military dictator Ayub Khan from 1963 to 1965 (and later prime minister), realised its 'potential' and popularised it at the mass level.