I think has more to do with geopolitics and international power play than law.
Correct...
In geopolitics power play rarely takes the law into account.
Ditto...
One of the most significant flashpoints in 20th century was the Cuban Missile Crisis where for a few days the world stood at the cusp of nuclear armageddon. What was it about that which warranted a nuclear war?
A sovereign state (Cuba) agreed with another sovereign state (USSR) to base misiles on it's own territory. The said missiles would be transported through international waters by ship. At no point were those missiles to enter any go anywhere near other state's jurisdiction. Thus this matter was entirely and exclusively within referance of Cuba and Russia. Can somebody here please cite what law this "transfer" contravened? I certainly can't think of any.
Forget about 12 nm. Cuba is nearly 100 nm distant from US coast and the missiles were based in sovereign Cuban territory. Given these facts can somebody explain how was it that USA came close to starting a nuclear war?
What was the legal basis to this? Was that an example of "unsafe" behaviour?
If the Soviet-Cuba alliance remained non-nuclear regarding the presence of Soviet military means, there would have been no 'crisis'.
The word 'geopolitics' really means how geography influences foreign affairs. Even though this fact was known for thousands of yrs, supposedly, it was Napoleon who put it best, something in the line of: Know a country's geography and you will understand its foreign affairs.
Collectively, nuclear weapons is an existential threat, even if that threat is stationed on the other side of the world with geographical respect to self. But even if a threat is existential, such a threat can have varying degrees of immediacy.
For example, a well known criminal armed with a machine gun is an existential threat to me, if he lives on the next block, it will take him a longer time to get to me than it would if he lives literally next door. Distance does not negate the seriousness of the
METHOD of the threat. A bullet is more assured of a kill than a stick, and we are talking about a method that can deliver multiple bullets in one second.
For a ballistic missile, 100 nm is well near literally nothing. Figuratively, it is nothing. Might as well have that machine gun poking inside my window. At that point, legalism be damned. I cannot afford to wait for the police, or in the Cuban Missile Crisis, a sort of a 'world police'. There was none in the first place. Under Fidel Castro, Cuba's geopolitics turned Cuba into a threat to the US. But Cuba did not have a machine gun but a cannon when Castro allowed the Soviet Union to station nuclear missiles on Cuba. No country would tolerate such a threat with that level of immediacy. How that country respond depends on its physical (military) prowess.
So was Cuba's behavior 'unsafe' ? In a manner of speaking: Yes.
It was 'unsafe' not in the sense of a pilot, a soldier, or a ship in danger, but in the sense that stability is threatened by a weapon that is yet to be matched in terms of destruction.