What are the legal standards for one country to annex another country or territory?

During World War II, the Axis powers (notably Nazi Germany, Italy, and Japan) seized and occupied countries and territories without concern for the health, safety, and basic rights of the people living in those lands. By the end of World War II, the world had seen enough of this behavior and wished to put an end to it. They held the Fourth Geneva Convention, and listed requirements for treatment of people during war and occupation. They also created the United Nations, with laws regarding nations’ actions. Article 2(4) of the United Nations charter states clearly that the use of force to acquire lands (as was common up to that time) is no longer legally permissible: “All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state.” Israel’s use of military force to occupy and control the West Bank and Gaza violates this provision of the United Nations charter. The United Nations has consistently stated that Israel’s military occupation is illegal.

There are several legal methods for a country to take land beyond its immediate borders. What these methods of acquiring land have in common is that land transfer can occur only if the people affected by the transfer agree to it, and if this agreement follows an extended period of peace, not during times of conflict. Israel’s actions do not suggest it is pursuing such peaceful methods in the case of the West Bank or Gaza.