Author of Mishneh Halachos and Ungvarer Rav
Rabbi Menashe Klein's Position on City Eruvin and the Rebbe
Rabbi Menashe Klein wrote on eruvin and is cited in the Chabad discussion of the Rebbe's position in large cities.
City-eruv questions
Rabbi Menashe Klein wrote extensively on practical halacha, including eruvin in modern cities. These questions bring together the definition of reshus harabim, the effect of six hundred thousand people, the width and course of public streets, and the possibility of enclosing a city through walls or tzuras hapesach.
His discussion belongs to the broader halachic background surrounding New York eruvin. It does not reduce the issue to whether a particular pole or wire was installed correctly; the status of the city itself remains fundamental.
His understanding of the Rebbe's approach
Rabbi Klein is also cited among the distinguished Rabbonim who understood the Rebbe as opposing the public establishment of eruvin in large cities. The concern was practical: once an eruv is announced, many people will carry without knowing the disagreements or the limits on which it depends.
The Rebbe's own letters and talks are presented separately in full where available. Rabbi Klein's relevance is his place within the rabbinic reception of that position.
Crown Heights
Crown Heights raises both parts of the question. It is a neighborhood within a large city, and it is governed by a local Beis Din that has rejected the advertised route.
The direct psak for residents and guests comes from the Crown Heights Rabbonim. Rabbi Klein's writings and public role help explain the wider large-city discussion in which that local ruling stands.