I know this is a very old thread, but its relevant to my question.
I saw a show the other day that followed two US DEA agents through a couple of operations in Columbia. Toward the end of the show they showed some footage of some subs that they have captured. The narator mentioned that these subs had a range of 3000 miles and could easily make it to coastal USA, carrying tons of drugs. He then went on to suggest that Al Quaida was beginning to integrate their oprerations into the Columbian cartels, for purposes of generating revenue, furthering their cause, etc. Imagine what a submarine or 10 full of explosives or chemical weapons could do. Is it realistic that the terrorist and the cartels could successfully work together in a symbiotic relationship or would the cartels sort of protect their money maker (us) from getting exploded.
Here's a link to the Wikipedia article on the subs: http://en.wikipedia.org/wiki/Narco_submarine