The Rebbe's Correspondence Concerning the Manhattan Eruv
In the Manhattan correspondence, the Rebbe considers the island's physical boundaries, directs questions to Rabbonim expert in hilchos eruvin, and warns against turning a disputed proposal into a public habit of carrying.
Bridges, tunnels, and the island boundary
Writing to Rabbi Hertze Eisenstadt (15 Iyar 5714), the Rebbe does not accept the claim that Manhattan is unquestionably a reshus harabim without further analysis. He asks how the bridges, tunnels, tzuras hapesach, barriers, and toll structures affect the city's perimeter.
The questions are concrete because a river is a boundary only until a public crossing pierces it. The letter leaves the final technical psak to those examining the city; it cannot be used as a general Manhattan heter.
Why the completion should not be announced
The letter to Rabbi Yosef Dovid Moskowitz (Rosh Chodesh Adar 5718) addresses what happens after an eruv is declared complete. A later break may be known to the people maintaining it while remaining unknown to the broader public.
The concern is not a remote engineering possibility. Once carrying becomes the visible norm, many users rely on that practice rather than a weekly technical report.
A Rav with particular expertise
In his letter to Rabbi Pinchas Weberman (3 Tammuz 5722), the Rebbe directs the matter to a Rav with special expertise in hilchos eruvin. The Manhattan problem joined reshus harabim, walls, gates, bridges, population, communal rights, and public reliance.
General rabbinic stature is not presented as a substitute for close experience in this area. The public heter must come from someone able to apply the sugyos to the physical city.
Rabbi Eliyohu Jung and the public presentation
Rabbi Eliyohu Jung was closely involved in the Upper West Side and Manhattan eruv effort. In the letter sent to him on March 30, 1964, the Rebbe addresses the halachic controversy and the use of respected rabbinic names in promoting the project.
A carefully qualified private view can become a broad impression that the city has been permitted. The Rebbe warns about the responsibility created when those names lead the public to carry, while later limitations reach only a fraction of the same audience.