What is so difficult about developing nuclear weapons that makes some countries incapable of making them?

Question

What is so difficult about developing nuclear weapons that makes some countries incapable of making them?

In: 1394

Answer 1

Most of these answers are really spot on, I would just like to add the fact that the “principles” of nuclear weaponry are surprisingly simple, see the wikipedia articles. However, the actual construction of one is the essence of the idiom: “the devil is in the details”