If the Knesset approves a peace deal involving givig to the other side some territory where Israeli law applies, then according to Israeli custom, this approval should work. If one wants to legislate an appeal on Knesset decisions, it may need to be enshrined in a Basic Law, otherwise the appeal may appear unconstitutional. (Strangely, Basic Law: The Knesset does not specify the functions of the Knesset, these are only customary.) It is not clear to me why the authors of the bill did not place it as an amendment to a Basic law. The Supreme Court may declare it "unconstitutional", based on customs. But who knows? This is a case without precedence.
5 wounded Syrians rushed to northern Israeli hospital (Haaretz)
from the article: Referendum: Decision by guillotine