I once heard a prominent Gush-Etzion Rabbi claim that we know land-for-"peace" agreements are Halachicly viable since in Sefer Melachim, Shlomo HaMelech A"H gives Hiram 20 cities in the Galil.
The verses in question are the following (מלכים א ט:י-יג):
וַיְהִי, מִקְצֵה עֶשְׂרִים שָׁנָה, אֲשֶׁר-בָּנָה שְׁלֹמֹה, אֶת-שְׁנֵי הַבָּתִּים--אֶת-בֵּית יְהוָה, וְאֶת-בֵּית הַמֶּלֶךְ. חִירָם מֶלֶךְ-צֹר נִשָּׂא אֶת-שְׁלֹמֹה בַּעֲצֵי אֲרָזִים וּבַעֲצֵי בְרוֹשִׁים, וּבַזָּהָב--לְכָל-חֶפְצוֹ; אָז יִתֵּן הַמֶּלֶךְ שְׁלֹמֹה לְחִירָם, עֶשְׂרִים עִיר, בְּאֶרֶץ, הַגָּלִיל. וַיֵּצֵא חִירָם, מִצֹּר, לִרְאוֹת אֶת-הֶעָרִים, אֲשֶׁר נָתַן-לוֹ שְׁלֹמֹה; וְלֹא יָשְׁרוּ, בְּעֵינָיו. וַיֹּאמֶר--מָה הֶעָרִים הָאֵלֶּה, אֲשֶׁר-נָתַתָּה לִּי אָחִי; וַיִּקְרָא לָהֶם אֶרֶץ כָּבוּל, עַד הַיּוֹם הַזֶּה.
(Translations by Machon-Mamre) And it came to pass at the end of twenty years, wherein Solomon had built the two houses, the house of the LORD and the king's house-- now Hiram the king of Tyre had furnished Solomon with cedar-trees and cypress-trees, and with gold, according to all his desire--that then king Solomon gave Hiram twenty cities in the land of Galilee. And Hiram came out from Tyre to see the cities which Solomon had given him: and they pleased him not. And he said: 'What cities are these which thou hast given me, my brother?' And they were called the land of Cabul, unto this day.
The same story is re-told in Divrei HaYamim but here Hiram is the one giving the cities to shlomo (דברי הימים ב ח:א-ב):
וַיְהִי מִקֵּץ עֶשְׂרִים שָׁנָה, אֲשֶׁר בָּנָה שְׁלֹמֹה אֶת-בֵּית יְהוָה--וְאֶת-בֵּיתוֹ. וְהֶעָרִים, אֲשֶׁר נָתַן חוּרָם לִשְׁלֹמֹה--בָּנָה שְׁלֹמֹה, אֹתָם; וַיּוֹשֶׁב שָׁם, אֶת-בְּנֵי יִשְׂרָאֵל.
And it came to pass at the end of twenty years, wherein Solomon had built the house of the LORD, and his own house, that the cities which Hiram had given to Solomon, Solomon built them, and caused the children of Israel to dwell there.
There are two problems with these passages. For one, there is a Commandment against giving Gentiles a foothold in the land, much less handing over entire cities. Second, how do we resolve the contradiction between the passages. The Abarbanel, in his commentary on Melachim offers the following resolution:
It is very difficult how Shlomo could have sold 20 cities, thus diminishing the size of his kingdom and giving the land over to gentiles against an explicit Command.
Thus, I think that Shlomo ... after he established his kingdom, saw fit to give to Hiram cities from the Galil, not so that those cities should become subservient to Hiram and not so that he (Hiram) should be master over them and thus subjugating the Israelites living them to the king of Zur, since if he would have done this, he would have been transgressing a Command of the Torah. Rather nature of [Sholmo's] present was that from those cities, [Hiram] would collect the wheat and the oil that Shlomo owes him. Thus the produce would be Hiram's while the sovereignty would be Shlomo's...
Now Hiram went out to appraise these cities to see if they were capable of producing the amount Shlomo had given him and 'and they pleased him not', since it seemed to [Hiram] that they would not produce so much wheat and oil. Thus he called them 'Eretz Kabul' which means - land that does not give fruit as Chazal interpreted it (שבת נד ע"א). Thus the present was paid in produce and not land.
According to this it is easy to understand the discrepancy in the verses. At first Shlomo gave Hiram the produce of the cities in question. Later when Hiram appraised the land and was not satisfied, he gave the cities back.
Even if we were to read the verses the way the Rabbi from Gush Etzion intended, then we would have to conclude that Shlomo sinned in this episode. In the end, we just don't learn Halacha from Nach.
