They've made this known for decades. However, the recent "intifada support conference" in Tehran made it crystal clear. The leader of Hamas and Iran's supreme ayatollah Khameni openly called for Israel's destruction in a public forum.
Palestine would not only be a newly established enemy state within spitting distance of Israel, it would also have an immediate ally in Iran; the world's biggest state sponsor of terrorism, with goals to be a nuclear power.
I've rode along the “Green Line” that separated Jordan from Israel prior to 1967....it's in downtown Jerusalem not way out along some waste land.
If I were Israel I'd start the conversation all over again and ask the Palestinians which country do they want airline tickets to and push them out of the West Bank and Gaza. I'd rather live next store to alligators than what the Israelis have to contend with on a daily basis.