On January 26, 1999, the Knesset passed a bill that would require a national referendum on any government decision to withdraw from the Golan Heights, officially annexed by Israel in 1981. The bill stipulates that a government decision to cede the Golan back to Syria would have to be approved by at least 61 of 120 members of the Knesset.
In November 2010, the Knesset passed an amendment to the Referendum Bill that renewed that requirement for a Knesset vote on any planned withdrawal from the Golan Heights in addition to stipulating a referendum on a withdrawal from East Jerusalem. The new amendment, which was supported by Prime Minister Benjamin Netanyahu, passed by a vote of 65 to 33 with no abstentions.
Under the new legislation any government signing a peace agreement ceding the annexed territories of East Jerusalem or the Golan, or any other sovereign territory within Israel itself, would be unable to implement the treaty without the approval of parliament and a national referendum.
Sources: AP (January 26, 1999); JTA (January 27, 1999); AFP (November 22, 2010)