During the Cold War era, the idea of nuclear war went hand in hand with the doctrine of mutually assured destruction. The Cold War is over. It's a new game.
Whether they publicly acknowledge it or not, a lot of countries have nuclear weapons and the means to deliver them. Within the next few years, many more will. Some of the countries that have or will have nuclear weapons are run by people who are not known for mental stability. Many nuclear equipped countries are not politically stable. Many do not have full control of their military. The doctrine of mutually assured destruction doesn't have the currency that it once did. Sale or trade of nuclear weapons to countries that do not have the technology to produce them is not an unlikely prospect and may have already happened. During episodes of regime change or political upheaval, ownership of nuclear weapons has become unclear. Not all weapons known to have been produced have been reliably accounted for. The Afrikaners disposed of their very excellent, Israeli designed nuclear weapons and delivery systems, before they turned their country over to Mandela. Who's to say some of the military custodians, soon to be out of a job and a country, didn't sell a few off to ensure a comfortable retirement in exile? No one even pretends to know what happened to all the USSR's nukes. There never even was a reliable inventory.
I was expecting an Indian/Pakistani nuclear engagement in the early-mid '90s. So far, it hasn't happened but still remains a strong possibility. There are several countries which might attack Israel with nuclear weapons and Israel would certainly respond or even carry out a preemptive strike if they had good intelligence that an attack was coming.
There has never been an effective weapon invented that wasn't used and used often. I think it's only a matter of time before any number of small nuclear wars and perhaps even a big one or two break out.
What do you think? Who will attack who? Who will win? Or will anybody?