The modern Jewish state of Israel has been based on a two-state partition of the British Mandate of Palestine since the Jewish state was created by the UN under this principle in 1947. It's even referenced in Israel's declaration of independence of May 15 1948. As others here have pointed out, it has been the Arab League since that time that has supported a one-state solution. Only recently (last 16 years for the PLO, seven for the League) has the two-state scenario been adopted.
One child, police officer killed in attacks in Diyarbakir in southeast Turkey (Reuters)
from the article: One-state solution is a blueprint for a nightmare