does lo techanem apply to aku"m only? heter mechira, land for peace

Shu"t v'Darashta v'Chakarta (vol 1 OC 54:3) responds to someone who claimed that lo techanem applies only to ovdei avodah zarah by saying that this is a chiddush gadol that requires proof to be believable, especially given that Tos seems to say otherwise. Tos in A"Z 20a interprets the issur broadly, writing that it applies not only to the 7 umos, but to all ovdei aku"m. The chesronos ha'shas quotes the girsa of Tos as reading "kulhu umos," not just ovdei a"z. Why narrow the issur when you see the reverse trend in Tos?

B'mechilas kvodo, not so fast. Ralbag in last week's parsha comments on the pasuk (14:21) לֹא תֹאכְלוּ כׇל נְבֵלָה לַגֵּר אֲשֶׁר בִּשְׁעָרֶיךָ תִּתְּנֶנָּה וַאֲכָלָהּ אוֹ מָכֹר לְנׇכְרִ that the reason the pasuk speaks of giving away neveilah to a ger but when it comes to an aku"m is specifies selling it is because:

והנה לא רצה השם יתעלה שתתן אותה לנכרי לפי שהוא עובד עבודה זרה ולזה לא רצתה שנהנה אותו מתנת חנם.

According to Ralbag, the issur of lo techanem is limited to ovdei a"z.

While the Rambam's view in Hil A"Z 10:3-4 is less clear, in Sefer haMitzvos he refers specifically and only to ovdei a"z:

הזהירנו מהושיב עובדי ע"ז בארצנו כדי שלא נלמוד כפירותם, באמרו לא ישבו בארצכם פן יחטיאו וגו', ואילו רצה העכו"ם לעמוד בארצנו אינו מותר לנו עד שקבל עליו שלא לעבוד ע"ז ואולם עובדי ע"ז לא ישכנו עמנו ולא נמכור להם נחלה ולא נשכיר להם בית, ובבאור אמרו לנו הפירוש לא תתן להם חנייה בקרקע

And finally, Ramban in our parsha (20:18) writes as well:

והנה בתורה הזהיר: לא ישבו בארצך פן יחטיאו אותך לי כי תעבוד את אלהיהם כי יהיה לך למוקש (שמות כ״ג:ל״ג), והיא אזהרה בעבודה זרה, כי אם תכרות להם ולאלהיהם ברית, ישבו בארצך הרבים מהם יפתוך לעבוד עבודה זרה.

It is not outlandish at all, and in fact, seems to be the dominant view in Rishonim, that the issur of lo techanem is limited to ovdei a"z.

This is not a trivial issue.  It impacts two major contentious issues:

1) Land for peace -- can we trade control over territory in Eretz Yisrael for peace (assuming the theoretical possibility of such an agreement holding water) with the Muslim population, who are not ovdei a"z?  I am surprised that R' Hershel Shachter (RJJ Journal #16 )in discussing this issue writes, "Although such an act [trading land for peace] would be a violation of the injunction of lol techanem... it is permissible in the interest of avoiding a situation of sakanat nefashot." Before getting to the question of whether there is a heter pikuach nefesh, one can question the fundamental premis of whether lo techanem even applies when not dealing with ovdei aku"m. (Aside from the issur of lo techanem, according to Ramban, there is also a mitzvas aseh of kibush ha'aretz.  Whether when the Torah mandates milchama, which by definition entails casualties, there is any heter pikuach nefesh is another major issue that is not my topic here.)

2) Heter mechira -- can we sell/lease land to Muslims for the duration of the shemita year so that farming can continue? The Chazon Ish writes that doing so constitutes an issur d'oraysa of lo techanem, but R' Ovadya points out that before getting into the nitty gritty of whether sheviis is d'oraysa or whether a temporary sale actually amounts to ceding control and is a violation of lo techanem, the fundamental flaw in the C.I.'s position is that according to many Rishonim lo techanem cannot apply unless you are dealing with ovdei a"z.