Many people approach this issue by focusing on the land and territory of Israel. While, it is certainly true that all of the land of Israel is holy, the Rebbe said that the issue of "land for peace" is not so much an issue of land per. se. - but rather an issue of preserving Jewish lives, regardless of location. The Shulchan Oruch (the Code of Jewish Law) states:
Non-Jews that lay siege to Jewish cities: If their intent was financial gain, the Shabbos laws should not be violated because of them. If their intent was against Jewish lives, or if they lay siege without any stated intention, or if there is a sense (chush) that they are coming for Jewish lives, then even before they come - and are only mobilizing themselves, it is a mitzvah to go out and attack them with weapons of war and violate the Shabbos laws. And if it is a city located near a border - even if they are only demanding hay or straw, we attack them and violate the Shabbos, lest they conquer the city, and because of that conquest it becomes easier for them to conquer the rest of the land.
There are those (rabbinic authorities) who say, that at this time, when we dwell among non-Jews who are murderers and slayers, that even if they come only for financial gain, we violate the Shabbos. Because, if the Jews do not allow them to plunder and pillage, they will kill us. And it is a chazakah (a given) that no one stands-by idly, when his money is being stolen. Thus, a thief coming to steal will worry whether his victim will kill him, so the thief comes from the outset with an intention to kill first. So also, in this case [where we are dealing with only financial attacks] we violate the Shabbos [to defend ourselves]. Nevertheless, everything is according to the context. But an individual, that comes to take money, we allow him to take as much as he wants, and we do not violate the Shabbos, for this is a case of financial loss only.
Shulchan Oruch HaRav 329:6,7. And almost the same wording can be found in the Shulchan Oruch of R. Karo, and also in the Mishna Berurah (same siman). See also Eruvin 45a including the Rashi. The Rambam adds:
It is a mitzvah for every member of the Jewish people who can come [to their assistance] to go out and aid their brethren who are under siege and save them from the gentiles [although it is the] Shabbos. It is forbidden to wait until Saturday night.
After they have saved their brethren, they may return home with their weapons on the Shabbos, so that a dangerous situation will not be created in the future.
Rambam, Mishna Torah, Hilchot Shabbos, 2:23.
From this we see a couple of things:
It should be obvious that since it is a mitzvah to aid our brethren, we should not do actions that the Shulchan Oruch states would endanger our brethren. Sadly, not all Jewish people recognize the authority of the Shulchan Oruch, and to our greater grief, there are those who re-interpret or ignore it (either due to ignorance, or to appear correct in the eyes of non-Jews, or other reasons).
Irrespective of this, we must work with our fellow Jews, and educate them to this important issue of saving Jewish lives, and how it applies to the "land for peace" issue. Most importantly, we must do this in a peaceable manner, for "the ways of the Torah are peaceful." With a peaceful, patient and understanding approach, certainly HaShem will aid us and help us to accomplish His will. However, we must be clear, certain, and confident; and this can only occur when we act according to the guidance of the Shulchan Oruch, and the teachings of our Rabbis.
Author: Yechezkal-Shimon Gutfreund