Maybe not. But it probably could be placed in the hold of a ship and detonated in New York Harbor.
Maybe not. But it probably could be placed in the hold of a ship and detonated in New York Harbor.
They definitely can be placed in a (heavy) suitcase, and the Russians have done so. This is not in dispute. General Lebed (Russian) has publicly charged on a number of occassions that a number of these are missing (the number missing varies depending on the source, but may be as high as 100).
The Russina government officially denies that any nukes of any kind are missing. Some U.S. officials have publicly stated that Russian nukes are missing, and some have stated the opposite.
The U.S. has also built a number of very small nukes. At one point in the past, we built nukes for tactical use that were small enough to be used on field artillery warheads. We built small nuclear mines to be placed on enemy ship hulls by navy divers. We even built small, remore controlled nuclear land mines intended to choke off Russian tank advances into Europe (never deployed, however).
Even though they can be made very small and hard to detect, your comment about placing them in the hold of a ship is right on the money.
They are so valuable that I doubt the terrorists would be willing to risk even a small chance that they would be caught smuggling one into the country. Putting one into a container is a guaranteed way to get it into position in a major harbor. These containers are almost never inspected on the high seas. A small number are inspected once the ship is in port, but that would be too late. If we started to open the suspect container, they would simply set the bomb off.
Obviously, they could already have smuggled a bomb in and pre-positioned it anywhere in the country. But if they have not, a cargo container on a ship is almost unstoppable on our end. If we found out it was coming, we could stop it on the high seas. It is also possible we could stop it when it is loaded, but that would require help from the country of origin.
Bottom line: If they have a nuke that they know how to detonate, they can almost certainly get it into position.