MrJonno wrote:The Germans took the channel islands. That's a different animal altogether.
We choose to not even try and defend it knowing the Germans were coming, not sure that is different to giving it to them. We also told the inhabitants not to resist (as it was pointless)
Because the Germans were the most powerful military in human history. You chose not to defend it because you knew you'd be pulverized. That was tactics in a larger war, and is not in any way a factor here.
MrJonno wrote:
India was British, but India wasn't empty when the Brits got there. The Brits conquered it, made a colony of it, and exploited its people and resources for the benefit of the British Crown and country
How do any countries form?, one group or the other takes other it kills ,expels or enslaves (they may already be living) , or at least subjugates any other groups present . This continues until another group does the same. Basically nation creation = genocide
Be that as it may, it is irrelevant to the present case. In the present case of the Falklands, they were empty when the Euros got there and no country had claimed it. Argentina did not exist. The Brit claim goes back to before Argentina even existed.
So, the question is not whether Argentina can assert dominance by conquest by pushing the Brits out and saying "we own it now, come and get us out if you dare." The question is whether Argentina has a legal claim to the islands. it doesn't.
Nation creating was indeed the way you describe up to a certain point in the first half of the 20th century. With the advent of the League of Nations and its successor, the United Nations, and soon to be the United Federation of Planets, there is an international law regarding these matters and it is no longer "legal" to conquer lands that have people on them.