Once a country becomes nuclear, there is very little that can be done if they want something.
Just wait until Iran comes out of the closet with a few hundre working bombs.
Therein lies the great danger - much greater than events preceding WW1 or WW2. With the US (and most of its people) proven dishonorable / selfish and worthless, and its protective umbrella discredited (or becoming so fast), any country capable of going nuclear doesn't really have much choice but to do so. With many nuclear powers in the world, the chance of a miscalculation leading to a significant nuclear exchange becomes a virtual certainty.