Yes USA plans a lot of stuff, does it all work out as planned? a big red NO!
Pakistani nukes are not ak47s you can pick one up from Kahuta Vault, pack it real nice in a suitcase and away you go.
There is a security apparatus in place which ensures that they are very very secure. The technology was acquired after much hardwork and will not just be handed over to uncle Sam.
Though some would like to see that happen, or pretend it would be that easy. It is not. Pakistani Armed Forces i’m sure have plans about plans of others in case such a situation arises. So all is well. 
in short, “if they coulda, they woulda”