Since I saw this posted on a mail list and is already online, I am posting it here as well.
In 1920, after the end of WWI, the victorious allies met in San Remo, Italy, to decide on the disposition of territory that had been under the control of the defeated Ottoman Empire. It was decided that Great Britain would be given the Mandate for Palestine. This was predicated on the Balfour Declaration that acknowledged the historical connection of the Jewish people to the land between the Jordan River and Mediterranean Sea, known as Palestine. It was determined that a homeland for the Jews was to be established in this area, and that close settlement of Jews on the land was to be encouraged.Technorati Tag: Israel and Settlements.
In 1922, the League of Nations unanimously approved this Mandate, which has never been superseded in international law.
When the Arabs began to generate disturbances because of Jewish settlement, the General Assembly of the UN (which had assumed all responsibilities of the League of Nations) voted in 1947 to recommend a partition of the land into two states -- one for Jews, one for Arabs. Note, please that I say recommend. GA votes carry no weight in international law -- they are only recommendations. As it was, the Arabs rejected the recommendation anyway. The Jews honored the recommendation, and so declared a Jewish state in 1948 on only a portion of Palestine. But this does not mean that the status of the other portion had changed. It was still Mandate land -- now, unclaimed Mandate land.
In 1949, at the end of the War of Independence (a war fought when the Arabs attacked the new state of Israel), the Jordanians had the eastern portion of Palestine. Jordan's occupation of this area was illegal as it was acquired in an offensive war. An armistice agreement was signed at that time between Israel and Jordan, and an armistice line was drawn, delineating the areas of control. This armistice line is the Green Line. It was NOT a border and was NOT intended to be permanent.
In 1967, in the face of existential threats -- primarily by Nassar -- Israel initiated a pre-emptive attack on the surrounding Arab states that were poised to attack Israel. This is an important point. It's not who attacked first that is key -- it's the intention, offensive or defensive. Israel's action was defensive. International law does differentiate between the two.
In the course of that war, Israel acquired Judea and Samaria. After the war, the UN Security Council passed resolution 242, which did NOT require Israel to return to the Green Line. It was acknowedged that additional strategic depth was required by Israel and the Green Line would not constitute a defensible border. It is my understanding that internationally it often happens that when a nation fights a defensive war, it is recognized that return to the original borders would be unsafe and some additional land is acquired.
Add to this the fact that nothing in the subsequent Oslo Accords prohibits Israel's building in Judea and Samaria. Resolution 242 and a number of other subsequently are clear on the fact that disposition of the land can be determined only via negotiations. Judea and Samaria remain unclaimed Mandate land, to which Israel has the strongest claim -- which claim was made stronger by the fact of the defensive nature of the Six Day War.
Yes, there was movement to determine that the settlements are "illegal" but this is a highly politicized anti-Israel position.