Heter mechira is one of the most controversial aspects of shmita. I will try to present all sides of the issue so each of you can form your own opinion.
In the 1500s there was a debate between Rabbi Yosef Caro and Rabbi Moses ben Joseph di Trani (ha Mabit) as to whether agricultural products grown in Israel by non-Jews were subject to shmita observance. Rabbi Yosef Caro permitted Jews to eat this produce while ha Mabit did not. This issue was of great importance in that day because there was no Jewish agriculture- the Jews were reliant on Arab produce for their subsistence.
Moving ahead to the late 1800s, where the Jewish settlers of the first aliyah movement were producing wine and citrus fruits. The settlements had previously been under threat of collapsing and were saved by Baron de Rothschild. The year 1889 was a shmita year and the settlers were genuinely afraid that they would not survive. They petitioned the Rabbanut at that time to issue a heter- permit- to allow them to work the land but were refused. They then took their campaign worldwide stating that it was a case of pikuach nefesh- saving a life- to which all law is to be put aside. Three rabbis in Eastern Europe- Samuel Mohilever of Bialiystok, IJ Trunk of Kutno, and Z. Klepfish of Warsaw agreed to a heter which permitted the land to be sold to Arabs for two years on the condition that work would be carried out in specific ways. Firstly, if affordable, non-Jewish labour should be used. If the settler was to poor, he/she could work on the land under the supervision of the Rabbanut which would permitted only work that was forbidden under rabbinical law. They also required the approval of the Gaon of Kovno, Rabbi Isaac Elhanan Spector, who agreed. Despite that, there was great controversy amongst prominent rabbis who felt that the Jewish community was not in such dire straits at that time. There were also rabbis who felt that observing shmita was a Torah law and not a Rabbinic law and therefore it is impossible to allow legal loopholes.
In 1895 a new version of the heter mechira was presented. It applied only to fruit trees and not the land, which allowed the settlers to still sell their fruit. This did not apply to other agricultural products. It also did not allow performing work on the trees unless it was to save the life of the tree, which is permitted anyway. The Arabs were supposed to cut down the trees, but if they didn’t the contract would be void and the ownership would return to the Jews. This heter was also applied in 1902.
In 1910 Rav AI Kook renewed the general heter mechira, albeit reluctantly. In a letter to the Ridbaz, Rabbi Kook wrote:
“I have said before that the halachic validity of the heter mechira cannot be doubted. Nevertheless this fact does not absolve us from our duty to seek out all opportunities the Almighty affords us and which enable our brethren who have settled in the Holy Land to observe shmita fully without having to resort to the heter mechira and any part of the Holy Land be it ever so small, where Jewish settlers keep the mitzvah of shmita in its entirety- כהלכתה- should be a cause of jubilation for us as if we had discovered the greatest treasure. But far be it from us to level accusations against those Jewish settlers who make use of the heter mechira. Although this heter is not an ideal thing- משנת חסידים- and our hearts ache because of the deplorable plight of the Jewish settlers in our Holy Land who are forced to take recourse to such legal devices which temporarily suspend the holy and beloved mitzvah of the Sabbath of the Land, nevertheless what has been done out of dire necessity is ‘perfect Torah’- תורה שלמה. And it behooves the great Sages of Israel to comfort those of our brethren who, with broken hearts, find themselves constrained to make use of such legal devices, so that they should not appear as law-breakers, God forbid, in their own eyes. To enlarge the Jewish settlement in the Holy Land is a religious duty that devolves upon all Jewish generations and the strengthening of the Yishuv brings nearer our final redemption when we can fulfill the law of shmita in its entirety.”
The Ridbaz disagreed with Rav Kook and claimed that eating shmita produce as a result of forbidden activities was akin to eating pork. Divine redemption, he said, will only come if we are observing shmita and not looking for excuses not to observe. Rav Kook felt quite strongly that if people saw farmers struggling to survive, it would prevent people from wanting to move to Israel; one of the most important concerns of his time.
In 1935, the Chazon Ish published a review of all of the previous discussions regarding shmita and came to the conclusion that there is no halachic basis for the heter mechira.
The Chief Rabbinate continues to renew the heter mechira each shmita year. There are fundamental differences between the heter mechira of colonial Israel and the modern state of Israel. In previous times, each farm performed a heter individually. In modern times, the Rabbinate performs a mass sale to one Arab, which leaves doubt as to whether the intention is for it to be a real sale. In addition, we would be hard-pressed to say that observing shmita would cause physical ruin to the Jewish State. Finally, in comparison to the religious Jews of colonial times who petitioned for a heter mechira because they were afraid for their lives, the great majority of farmers in Israel are not Sabbath observant. What is the most acceptable method to deal with non-religious farmers? One cannot neither force them to observe shmita nor forbid their produce from entering the market. Therefore using the heter mechira is considered the best alternative.
The most difficult issue with the heter mechira is the visceral reaction most people have to the State of Israel selling its land to an Arab. So many people have died to preserve the State of Israel that it seems criminal to sell it. In addition, the heter is only valid if the sale is intentional and not symbolic, which makes matters even worse.
There are people who believe in the validity of the heter mechira based on the opinion of Rav Kook. The Kibbutz HaDati movement is the largest movement that supports the heter mechira in this time. Another group of people who use the heter mechira are farmers who live in areas that are in doubt as to whether they are within the borders of Israel- the south and the Beit Shean area for example. They use it as a safeguard in cause the doubt is incorrect.
Charedi farmers do not hold by the heter mechira and observe shmita by leaving their land fallow and hefker (ownerless). They receive subsidies from the Ministry of Agriculture during shmita to prevent them from falling into dire financial straits.
Source: Shemittah and Yobel by Dayan Dr. I. Grunfeld.
Same chips, different hashgacha and therefore different sources of potatoes.