1950 Technology - Nukes to you

Operational in 1952 and using the technology that was top of the line in 1952 comes the Mark 7 - a nuclear bomb of a small enough size to fit on the planes of the day. A few years later there were hydrogen bombs this size that fit on planes. This would be nuclear weapon technology 50 years old. The usual official Government talk states something about nuclear weapons being too large to be easily transportable. It seems to me this would not be the case. Even with overly large 50 year old technology a nuclear bomb could be put in a truck, a boxcar or a shipping container with no difficulty. I think that in fifty years the technology available to interested parties would allow weapons of this size or smaller. I'd feel better about this if stories like this missile sales didn't happen with some regularity. The fact that the CIA and the US didn't know that about the Ukraine missile sales to Iran and China isn't unusual and when you think about the thousands of nuclear weapons from the former Soviet Union and the number of those nukes that are unaccounted for you might start to be concerned. The officials in the Ukraine said not to worry, we didn't sell them the nukes that were on those missiles. Self regulation, a beautiful thing and a wonderful thing to rest your security on.
I just think that when in five years or so when a nuclear bomb is detonated in the United States the cries of how could this happen will be deafening. By that time it will be too late. The rest of our civil liberties will evaporate along with part of a large city.