The Rebbe and Eruvin Established in Other Communities
The Rebbe's correspondence and responses concerning eruvin were not identical in every community. Some sources record approval or encouragement in a particular place. Others warn strongly against a publicly known city eruv, place the decision with local Rabbonim, or question why a Rav should enter a complicated eruv project at all.
Those records belong together only when their local settings remain intact. An eruv in one community does not establish the halachic status of the streets, boundaries, population, supervision, or rabbinic authority in another.
Kfar Chabad
A letter in Igros Kodesh to Rabbi Shneur Zalman Garelik, the Rav of Kfar Chabad, congratulates him on completion of the eruv there. The Rebbe wrote:
Mazel tov on the successful completion of the eruv. May it be G-d's will that through this additional action in matters of Shabbos observance, the time of our redemption in actuality be brought even closer, as is known from the teaching of Chazal that if the Jewish people would observe one Shabbos, they would immediately be redeemed.
The Hebrew is explicit: "מז"ט בעד גמר העירוב בשעה טובה ומוצלחת", a congratulation on the completion of that eruv. It is therefore not correct to turn the Melbourne material into a claim that the Rebbe opposed the existence of every eruv in every community.
At the same time, the Kfar Chabad letter is about the eruv of Kfar Chabad. It does not state that every large city has the same halachic status or that the same physical construction can be used in a different place. The Melbourne and Yagdil Torah responses themselves show why local facts matter: they speak about whether a place is suitable for an eruv, whether it contains a reshus harabim de'oraisa, what happens if the enclosure fails, and whether the eruv is publicized.
Rabbi Asher Herson's account from Rockaway
Rabbi Asher Herson later related an exchange concerning an eruv in Rockaway, New Jersey. In the public account, he describes asking the Rebbe around 5753 whether to undertake the project and involving Rabbi Shimon Eider, a non-Lubavitcher Rav known for expertise in eruvin. Rabbi Herson relates that the Rebbe directed him to proceed and added that it should be done "without delay."
The surviving public basis for this episode is Rabbi Herson's later testimony. The original written question and answer, an exact date, and the complete contemporaneous file have not been located. It should therefore be presented as his account, not as though an original Rebbe manuscript is presently available.
Even as testimony, the episode makes an important point. A local eruv question can depend on the actual community, the reason an eruv is being considered, and the expertise available to design it. It does not supply the missing halachic facts for a different neighborhood.
Miami is a separate record
A reported exchange concerning the Miami Beach eruv is also part of the wider record, but it stands on its own facts and provenance. Rabbi Shmuel Zajac has publicly related what Rabbi Shmuel Tuvia Stern reported from a Yud Shevat 5743 farbrengen. The complete treatment of that episode requires the reported exchange, its speaker chain, and the limits of the available audio identification to remain together.
It should not be reduced to a slogan for or against eruvin elsewhere. The reported Miami discussion concerns Miami and includes questions about the conditions of that city. It does not decide the status of Melbourne, Doncaster, Kfar Chabad, Brooklyn, or Crown Heights.
Why one community does not establish another
The differences between these records are not contradictions once the questions are kept intact.
In Kfar Chabad, the Rebbe congratulated the local Rav on completion of an eruv. In the Rockaway account, Rabbi Herson relates that he received direction to proceed with a local project involving outside expertise. In Melbourne, the Rebbe warned that a publicly known eruv could become a terrible stumbling block if people became accustomed to carrying and later continued when it was invalid. When the Melbourne dispute returned, he wrote that the decision depended on the local Rabbonim. In Doncaster, he reminded the local Rav of the complicated discussion and asked what compelled him to enter it. In the typed Yagdil Torah response, making an eruv is expressly conditioned on the absence of a reshus harabim de'oraisa, the place being otherwise suitable, and the eruv not being publicized.
The recurring principle is not that the name of a city decides the halacha by itself. The physical and halachic conditions of the place, the nature of the proposed enclosure, the expertise responsible for it, and the authority of the local Rabbonim all matter. For Crown Heights, those questions must therefore be answered from the facts of Crown Heights and from the rulings of the Crown Heights Rabbonim, not by transferring the status of another community's eruv wholesale.