In the event that the jihadists get close to it. From the National Terror Alert Response Center (thanks to Mackie):
US special forces snatch squads are on standby to seize or disable Pakistan’s nuclear arsenal in the event of a collapse of government authority or the outbreak of civil war following the assassination of Benazir Bhutto.
The troops, augmented by volunteer scientists from America’s Nuclear Emergency Search Team organization, are under orders to take control of an estimated 60 warheads dispersed around six to 10 high-security Pakistani military bases.
Military sources say contingency plans have been reviewed over the past three days to prevent any of Pakistan’s atomic weapons falling into the hands of Islamic extremists if the administration of President Pervez Musharraf appears threatened by civil unrest….