Well that is exactly why. Could you imagine the fallout of NK or Iran using nuclear weapons on an invading US allied force? It would unleash a clusterfuck of untold effects worldwide and probably a lot of death. There is a reason why they haven't been used in any conflict since WWII despite all this chaos in this world, they are a powder keg.

In the case of desert storm, The US along with 34 other countries were coming to aid of Kuwait which Iraq invaded and annexed over an oil spat.