Basic international law. If a country gives up its sovereignty, as did Jordan by its abandonment of the West Bank in 1967, the first country to occupy the place gains lawful sovereignty over the territory. This law has its parallel in private law of most nations. If someone abandons their personal property, the first person to take possession with the intent to excercise property rights over the object becomes the paramount owner. Check it out, if you have a modicum of balance.
Trump: Middle East would be more stable if Saddam, Gaddafi still in power (Reuters)
from the article: Saudi FM: Israel is acting like a spoiled child