From the NYtimes Op-Ed Page:
One possible plan would be a Special Forces operation with the limited goal of preventing Pakistan’s nuclear materials and warheads from getting into the wrong hands. Given the degree to which Pakistani nationalists cherish these assets, it is unlikely the United States would get permission to destroy them. Somehow, American forces would have to team with Pakistanis to secure critical sites and possibly to move the material to a safer place.
For the United States, the safest bet would be shipping the material to someplace like New Mexico; but even pro-American Pakistanis would be unlikely to cooperate. More likely, we would have to settle for establishing a remote redoubt within Pakistan, with the nuclear technology guarded by elite Pakistani forces backed up (and watched over) by crack international troops. It is realistic to think that such a mission might be undertaken within days of a decision to act. The price for rapid action and secrecy, however, would probably be a very small international coalition.
These guys clearly have been watching a little too much 24 lately, because the above plan is something that could only happen in a Hollywood script.
As Karl Sagan used to say "extraordinary claims require extraordinary evidence"... only in this case it is: "hopelessly dire scenarios require helplessly desperate solutions"... and you can quote me on that.