This is the problem with peace treaties. You can spend 20 years negotiating a treaty with one government then a little further down the line the government changes and they can tear up that treaty quite legally unfortunately once you have given them the land you can't ask them to give it back it they tear up the treaty. This is also why security needs to be one of the most important things for Israel to take into consideration when it comes to the idea of land for peace. We cannot assume that just because one government has signed a treaty that we will have peace. You must prepare for the worst all the time and hope for the best which is why its not just a simple matter of saying go back to the pre 1967 borders and all the threats will go away forever. Israel is just 9 miles wide in some areas, you can hit a plane taking off from Ben Gurion airport with a shoulder launched RPG from the Jordan Valley. A plane could take off from Gaza and crash into a tall building in Tel Aviv before you can scramble fighter jets to intercept. From the Golan you can fire down on the residents of the Galilee. Treaties don't guarantee peace but its not possible to defend the borders.
North Korea leader Kim Jong Un hails accord with South as landmark (Reuters)