Rav and author on the Rebbe's position concerning eruvin
Rabbi Shmuel Zajac on the Rebbe's Position and Eruvin in Large Cities
Rabbi Shmuel Zajac set out a sustained presentation of the Rebbe's position on city eruvin in a Hebrew study and a later English summary. His work brings together the Rebbe's letters and reported directives with the Alter Rebbe's halachos of reshus harabim, shishim ribo, and tzuras hapesach. It is an authored halachic analysis, not a Crown Heights Beis Din psak, and its importance lies in the argument Rabbi Zajac himself develops from those sources.
A public eruv and a hidden failsafe
Rabbi Zajac begins with the Rebbe's response that Rabbi Sholom Dovber Levin later published from his old Yagdil Torah papers. He understands that response as establishing two separate points.
First, even where a place is not a reshus harabim de'oraisa, a publicly relied-upon eruv can create a serious problem when the enclosure later fails and the public does not learn of the failure. Rabbi Zajac summarizes the point this way:
Even when there is no reshus horabim, an eruv should not be constructed due to the obstacles that will inevitably result.
His own footnote immediately qualifies that sentence. He distinguishes a public eruv from a discreet enclosure made only as a last-resort protection for people who would carry regardless. That distinction follows the underlying response, which speaks about making an eruv only where there is no Torah-level reshus harabim, where the place is otherwise suitable for an eruv, and on condition that it not be publicized.
Second, Rabbi Zajac argues that contemporary cities can contain a genuine reshus harabim de'oraisa. In his reading of the Alter Rebbe, an ordinary perimeter of poles and wires cannot permit carrying in such a domain, regardless of how carefully it is inspected.
The underlying response and what is known about its context are treated separately on The Rebbe's Yagdil Torah Response on City Eruvin.
What is the mitzvah of eruv?
A central part of Rabbi Zajac's argument concerns the familiar ruling that it is a mitzvah to pursue an eruv. He points to Shulchan Aruch Harav 366:13, 366:18, and 395:1 and argues that the immediate subject there is eruvei chatzeiros and shitufei mevo'os, the shared communal eruv that permits residents of an already enclosed area to carry between their domains.
He therefore rejects turning that phrase into an automatic requirement to surround every city with poles and wires. The mitzvah assumes that the physical and domain requirements of halacha have first been satisfied. In his presentation, the purpose of the enactment is to prevent prohibited carrying. If a public eruv would instead lead people to carry after a failure, that concern belongs inside the halachic discussion rather than outside it.
The distinction between the physical enclosure and eruv chatzeiros is explained in full on What Makes an Eruv Valid and Eruv Chatzeiros and the Purpose of Eruv.
Failure, inspection, and continued reliance
Rabbi Zajac also addresses the argument that modern construction and weekly inspection remove the older concern that an eruv may become invalid. He says that people who inspect eruvin told him that contemporary eruvin still suffer damage, and he points out a more basic timing problem: an enclosure can fail shortly before Shabbos or during Shabbos itself.
His point is not that weekly inspection is meaningless. It is that inspection before Shabbos cannot guarantee that a failure will not occur afterward, and notification after a failure does not necessarily reach everyone who has become accustomed to carrying. He connects this concern to the Rebbe's repeated discussion of publicity and the difficulty of reversing public habits once an eruv is known.
At the same time, Rabbi Zajac distinguishes between encouraging reliance on an eruv and improving an eruv that people are already using. Where people will carry in any event, making an existing enclosure as kosher as possible can prevent their carrying through a defective eruv. The Rebbe's broader treatment of publicity and failure is set out on The Rebbe on Publicizing an Eruv in a Large City, while the mechanics of checking and repairing an eruv are treated on Inspection, Maintenance, and Repair.
Shishim ribo and the city as a whole
Rabbi Zajac's second major subject is the meaning of shishim ribo, six hundred thousand. He rejects the proposition that the criterion can only be met if six hundred thousand people pass through one particular street or one particular point every day.
He bases his reading in part on the Alter Rebbe's formulations concerning a large city containing six hundred thousand inhabitants and a city through which six hundred thousand pass, and on the status of the encampment in the Midbar. From these sources he argues that the relevant public roads serve the city's great population even though all six hundred thousand do not physically cross the same small section of pavement during a single day.
That is Rabbi Zajac's halachic reading of the sources. The definitions of shishim ribo, the competing ways of counting it, and the New York figures themselves belong on the dedicated pages Shishim Ribo and the Requirement of Six Hundred Thousand and Shishim Ribo in New York City and Brooklyn.
Straight streets, walls, and tzuras hapesach
Rabbi Zajac also addresses several technical attempts to avoid the status of reshus harabim. He argues that the requirement for a road to run straight from gate to gate is specifically connected with a city enclosed by walls. In an unwalled city, he says, a road does not cease to be a public domain merely because it turns or intersects with other streets.
Likewise, he does not accept a general building-line argument that attached buildings form enough standing wall, omed merubeh al haparutz, to neutralize wide public street openings. In his presentation, sixteen-amah public breaches remain a serious problem, and a genuine reshus harabim requires the stronger remedy described by the Alter Rebbe, including actual gates rather than an ordinary tzuras hapesach of poles and strings.
These questions receive their full treatment on Reshus Harabim in a Modern City, Walls, Gaps, and Omed Merubeh, and Gates and Delasos.
Crown Heights in Rabbi Zajac's presentation
Rabbi Zajac points to the absence of a Crown Heights eruv throughout the Rebbe's leadership and to testimony from Rabbonim and Chassidim as part of his presentation of the Rebbe's position. He considers that history significant when explaining the Rebbe's position. His inference from the absence of an eruv is his own argument; the individual letters, recordings, and testimonies must still be read according to what each one actually preserves.
For Crown Heights itself, the present practical ruling does not depend on that inference. The Crown Heights Beis Din has repeatedly ruled that carrying in the neighborhood streets on Shabbos and Yom Kippur is forbidden. The local rulings are treated on The Crown Heights Eruv and the Rulings of the Crown Heights Rabbonim, while the Rebbe sources are treated on The Rebbe and Eruvin.
Rabbi Zajac also distinguishes communities such as Kfar Chabad and smaller towns from the large-city case he is analyzing. An accepted eruv in one place does not determine whether another place has the same domain, population, enclosure, and local rabbinic conditions.