🇺🇸🇷🇺 - Regarding the right of conquest.
During the Cold War, the general rule was that the right of conquest was abolished. As always, there exceptions, notably in former Mandatory Palestine, in East Timor etc, but it was broadly respected.
After the end of the cold war, the exceptions to the general rule of the end of the right of conquest got a lot more frequent: Kosovo, the successive tacit partitions of Syria, Libya and Yemen following the end of their civil wars, Crimea, Iraq, Afghanistan and finally 2022 with Ukraine.
But why was the right of conquest abolished in the first place?
Before the industrial revolutions, war were mainly an elite things. Nobles were doing the fighting, even if as always civilians casualties existed.
This means that the impacts of any result of war and peace was mainly upon nobles and sometimes the clergy. However, when the industrial revolution hit, the masses got involved. There were the napoleonic wars, the US civil war, WW1 and then WW2 which had the draft. All of this meant that govts, if they wanted to survive the war effort, needed to justify the war to their population. Thus, nationalism got stronger and, in the end, it caused a lot more of ethnic cleansing and genocides.
And turns out that, when 1945 arrives, and the allied troops discover the concentration camps, there was an international outcry. First of all, there were only 2 major powers remaining, both of which were nominally anti-imperialist, and then, guess what, people were sick of war. Hence the formal legal abolition of the right of conquest.