system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] How would King T'Challa stop the outside world coming to Wakanda to take Bucky Barnes?
gpt
Wakanda is a UN recognised country with no extradition treaty with the US, Russia, France or any other country that might have a claim to him as they are extremely isolationist.  So there is no legal way for them to come get him except negotiations.  If T'Challa still says no after negotiations it would be an act of war to try to come get Bucky, something most countries wouldn't want do for one man.  If someone did violate Wakanda, at least in the comics, they are very technologically sophisticated and easily defensible.  You would not be able to fight your way into Wakanda with standard military hardware found in MCU.  It would take a group of War Machine armors finally being developed by someone not named Stark.