Theres this place called the United Kingdom, and actually i think you'll find India isn't European, and South Africa does have nuchlear weapons. Since the 1940's i think.
First I mentioned countries that were not part of Europe or be part of the Middle for a reason.
Second, India currently have nuclear weapon (same as Pakistan but considering they would align with the Middle East ...)
Third, South Africa DOES NOT have nuclear weapons, they did had a nuclear program back in the 70's but it leaded to nothing, sort off ... depending if you want to count Israel or not.
Also United Kingdom have nuclear weapons since 1952, I have no idea why you think South Africa would be able to develop nuclear technology that fast, the UK was the 3rd nation with Nuclear capability, the Soviet Union first nuclear test was in 1949 and South Africa have independence since 1910 (even if it was just a dominion, they did leave the British Commonwealth in 1962 and became a Republic).
As a note, a lot of countries developed or tried to develop nuclear power, Germany and Japan for example are de facto Nuclear Powers despite having no nuclear weapons but we are just "guessing" what happened in Fallout universe, we have no idea if the various African independence movements succeeded or not.
European Commonwealth ceased to be, but some of the quarreling nation states certainly had their own nuclear arsenals, as they do in our world.
And they used said arsenal in a limited regional scale in the Middle East.
Point is, they would not just press the button without reason and honestly, they would had no reason to press it because the U.S. or China was about to being bombed and considering they were pretty much without oil one must wonder if they would even be capable of doing so.
And the Soviet Union could be at war with China as well, over the resources in Siberia. So their somewhat better relations with the US might simply be because of having a common enemy, just like during WW2. By the way, I wouldn't count out the Soviets trying to conquer Europe after the fall of the European Commonwealth. Perhaps Germany was united, but under communist rule?
And maybe the Soviet Union was saved by Communist Aliens and so the glorious People's Revolution continues to live on.
Look, we know the Soviet union existed in 2077, we have no evidence that it was a ally or enemy of China as there is almost no information beyond that simple note in a pre-generated character biography in Fallout 1.
I have to assume things based on evidence, there is none about the USSR involvement and so I have to presume with the lack of any reference they stayed out.
Also lets look at why China invaded Alaska ... it was the pipeline since China was running out of oil so, why Alaska and not the Soviet Union?
Chances are the Soviet Union was too much of a hard nut to crack and the Chinese would halt to a stop due to running out of fuel before they could secure whatever oil resources the Soviet Union had (and if they had it in enough quantity to justify the invasion oil cost), Alaska was a safer bet.
Also do not comparing with WWII does not work, the Soviet Union was attacked by Germany ... they were happy sitting the war out until the Germans decided to make then enter the war, the U.S. was a ally because of December 7, 1941 ... sure before that they were in the lease deal but hey, it was a Communist dying so a American would not ... it was keeping the war
in Europe and not in the U.S. backyard.
The quote from the wiki about other countries is actually from the original timeline written by the Fallout 1 devs.
And things changed, I doubt the Enclave and the Vault Experiment were considered back in Fallout 1 ... its not strange things were expanded, besides you have Fallout 1 developers with different ideas about how things even work (example, mutations).
Not the whole of Europe, but some European states could be. Some Middle Eastern countries probably had their own nuclear weapons too, as well as the countries you mentioned.
I am not saying they did not, I am just saying there was no reason for then to launch their nukes just because China and the U.S. decided to have a nuclear exchange.
And we do know that Britain is just as destroyed as the US, if not more (from Emil). According to Tim Cain, Vatican City got nuked too.
Vatican City is a small part of Rome, if Vatican City was nuked then Rome was nuked
And I disagree with the notion that the damage was directly caused by nuclear blasts of the Great War, besides explain to me how in the hell did he managed to cross the ocean in the first place if Europe was much destroyed as the US?
How the hell did we retained cross-ocean abilities when a)lacked fusion battery power technology, b)lacked oil to run the pre-war ship engines and c)were destroyed.
Serious ... I guess we could go back to sails and steam engines but how the heck we retained SHIPYARDS and why we would even brother? we knew America was right there but its not they can help so why?
Did we did for the win? were we just bored? or did we decided that hell, lets just build transatlantic ships and laugh at the Americans?
We don't have many mentions of other countries' involvement in the events, but this is simply because (as Chris Avellone said in the Fallout Bible), the devs don't want to be constricted when they eventually decide to set any future games there, not because they were not involved at all. Therefore they just made vague mentions of "other countries" without giving any details.
And the same goes for anyone claiming otherwise, I said Africa was irrelevant because ... I see no relevance, do you see any relevance or are just saying its relevant because
it might be relevant in the future?
That is absurd, I can only work with available data and make hypothesis based on the same data ... I do not decided on what that data is based on what it could be, also I try to make logical reasonings.
For example, the Enclave is the shadow government of the U.S. and they have a strict anti-communist rhetoric so logically they would not ally with a communist goverment.