The US government also had contingency plans for mail delivery after a "nucular" attack on the US. Such plans are more of "peace of mind" fetishes (no pun intended) than something that can produce tangible results. If seizing "nucular" weapons in a commando-style operation was feasible, would not the countries possessing them took steps to prevent such an action? Just think about the botched raid to free hostages in Teheran.
Another question - does Pakistan have the capacity to deliver "nucular" war heads to vital centers in Russia or even Israel, which involves the distance of 1500-2000 miles?
For countries like Pakistan, the most effective "use" of nucular weapons is as a threat - for their actual use is tantamount with suicide without even mortally wounding the enemy. Russia or even India would obliterate Pakistan if attacked by it, yet the damage they could sustain from such an attack, while serious, would not seriously weaken them.
Wojtek