To local residents, it might seem all too familiar.

At the turn of the millennium, a fight over an eruv in Tenafly that turned Jew against Jew — not to mention non-Jews, some of them newly inflamed anti-Semites and others befuddled onlookers, against Jews — took years to go through the court system, ending in a decision in favor of the eruv, and seemingly little change in the community.

In the end, after much sound and huge fury, not very much happened. The Tenafly eruv is now just another set of plastic markers and utility poles, similar to the ones in Teaneck, Englewood, Fair Lawn, Bergenfield, and other Bergen County towns, and for that matter like the ones in Monsey, New Square, and other Rockland County municipalities.

Now, there is an attempt to extend the Monsey eruv south into Bergen County, enclosing areas in Upper Saddle River and Mahwah, among other areas in the county’s northwestern corner.

The eruv is a combination of markers and lintels that mark metaphoric doorways, legal fictions that allow observant Jews to carry on Shabbat by creating boundaries enclosing domains within which carrying is allowed. (It’s complicated; we’ll explain more farther down in the story.)

In both Upper Saddle River and Mahwah, legal fights have begun. Upper Saddle River has hired two veteran eruv battlers and Mahwah has been the site of face-downs between three opposing groups as they triangulate the issue.

There also has been vandalism. Eruv markers have been vandalized in both Upper Saddle River and Mahwah; an accused vandal was arrested in Upper Saddle River.

Every eruv case is different. There will always be a different set of facts to be adjudicated. But it seems that there always is something all these cases have in common — the accusation of anti-Semitism, generally backed by some very nasty slung insults. Another thing they all seem to have in common is the assertion that it is not necessarily anti-Semitic to be anti-eruv. That just makes you anti-eruv. That assertion generally also is backed by hard facts.

Another thing that seems always to be true, at least around here, is that the fight gets ugly.

Mahwah has not yet decided how to proceed, its mayor, William C. Laforet, said. Its council has sent a letter warning that it has the right to issue summons for violations of its sign ordinance, which makes clear that no signs can be posted on its poles without permission. It has not issued any summons yet, although its lawyers and council members are meeting to discuss the town’s next steps.

Bruce Rosen of Basking Ridge, an attorney who represented Tenafly through most of its eruv fight, and Marci Hamilton, an expert on church/state relations who taught constitutional law at Yeshiva University’s Cardozo Law School until her recent move to the University of Pennsylvania, now are helping Upper Saddle River defend itself. Their experience in the eruv wars is extensive; Mr. Rosen represented the Westhampton Beach Alliance for the Separation of Church and State, which opposed an eruv in that New York town, and Ms. Hamilton did the same for the borough of Quogue. Both towns are on Long Island’s East End.

All those legal efforts failed in federal court, however.

In the last few weeks, both Upper Saddle River and Mahwah held city council meetings to discuss the eruv. Michael Cohen, the Englewood city council member who also is the Simon Wiesenthal Center’s eastern director, was at both of them, and he ended the evenings profoundly disturbed by what he saw there.

First, he went to the meeting in Mahwah.

“They did everything to stop me from speaking,” he said. The rules given to the huge crowd — he estimated it at perhaps 400 people, many of them in overflow rooms — were that they could not talk about religion or the eruv directly. In fact, he said, the meeting purportedly was to talk about “the engineer’s report, saying something about the issue that is being discussed, which is controversial — it was the most ridiculous way of not saying eruv or religion, or anything else for that matter. It was a comedy.”

But it wasn’t particularly amusing, he added.

Englewood City Council member Michael Cohen, who is also the Simon Wiesenthal Center’s eastern director, addresses the city council meeting in Upper Saddle River on the proposed eruv. Cohen also spoke before the Mahwah city council.

Englewood City Council member Michael Cohen, who is also the Simon Wiesenthal Center’s eastern director, addresses the city council meeting in Upper Saddle River on the proposed eruv. Cohen also spoke before the Mahwah city council.

There was an hour allotted to discuss the eruv — in other words — and each speaker was given only five minutes. Speakers from Mahwah were allowed to go first. “They let them go for 10 minutes each,” Mr. Cohen said. He was not allowed to speak, although he was the only person still on line when the hour — which stretched into an hour and a half — was over.

“They were saying things from an anti-Semitic perspective that would make your stomach turn,” he said. “People were saying things like ‘We don’t want these people in our town,’ and ‘If they can’t respect our town ordinances, then we don’t want them in our town.’ ‘These people are known to take over our parks and to take over our communities, and we don’t want them.

“They wouldn’t speak the word Jew. It was just ‘them’ and ‘those people.’”

“We do not NOT want these people living in our neighborhoods,” the Orthodox website VosIsNeais.com quoted Mahwah resident Robert Ferguson as telling the meeting. “”We welcome everybody.”

He noted that a recent ordinance barred nonresidents from using public parks, a measure passed in response to busloads of out-of-state visitors.

Sandy Eller, who reported on the gathering for VosIsNeais.com, wrote that as a visibly Orthodox person, “Several people told me I was not welcome during the meeting, and I had cell phone cameras shoved inches away from my face repeatedly as people snapped pictures of both me and my press credentials.”

Mr. Cohen waited until the meeting was over, when the floor was open for comments. He was told that he still could not speak about religious issues, and that because he represented a religious organization, the Wiesenthal Center, he could not speak at all. He said that the Wiesenthal Center is not religious; that explanation took up his entire five minutes.

A Holocaust survivor also spoke. “They heckled him,” Mr. Cohen said. “They heckled a Holocaust survivor.”

The next week, the meeting was in Upper Saddle River.

“It’s a fight that’s already been fought, but we’re going to do the best we can,” Mr. Rosen told an Upper Saddle River town meeting Thursday night. “These odds are against us.”

The gathering gave Upper Saddle River residents a chance to vent against the eruv — and out-of-town Jews a chance to defend it.

At the beginning of the meeting, Mayor Joanne Minichetti read a statement laying out the background to the eruv controversy.

She reported that the legal battle now is on hold. The borough has agreed not to enforce its takedown notice against the eruv immediately, and to allow the eruv to be repaired. A suit has been filed against the town in federal court in Newark. Upper Saddle River “will aggressively fight to enforce our ordinance,” Ms. Minichetti said.

She warned speakers that “This is a matter of excessive entanglement with religion and violation of municipal ordinances. It is not directed at any particular religious group. The governing body will not tolerate or countenance any anti-Semitic or otherwise discriminatory comments at our public meetings and urges residents to avoid any such statements on social media or elsewhere. Such statements will not be helpful to the borough’s position and are totally inappropriate.”

Mr. Rosen later restated this principle in advising how to talk about the issue — and how not to talk about it. “If you’re not careful about this, this can be a quick loss,” he said.

When the issue finally came to the floor, Mr. Cohen tried to speak, as he had in Mahwah; again, as in Mahwah, he was sent to the back of the line, after all the residents. When he finally was allowed the microphone, it wasn’t for long.

“The comments again were ridiculous in terms of their anti-Semitism and vitriol,” he said. “Finally, when I started speaking, I was heckled. I was constantly shouted down.

“I was trying to say that our message has been that we are not fighting about an eruv. We are fighting anti-Semitism. When I was cut off, I was saying that when you say you want to protect your city, dial it back.

“If you don’t want to have crowding, if you don’t want multiple unit housing, you can do that through your housing board. If parking is an issue, work through your traffic bureau. You can protect your city. But once you start saying you don’t want an eruv, you are crossing the line into anti-Semitism.”

Steven Young of Upper Saddle River told the gathering that “When it comes to religion, I support however people look at their religion. I have an issue where a town is allowing a religious statement to be committed on my property. If you want to move to this town, you’re welcome. Don’t ask us to conform to whatever your religion is.”

One longtime resident worried that the eruv would be followed by street lights and sidewalks, a loss of the borough’s rural character, which drew him there 50 years ago.

Another complained that the eruv was demarcated with white PVC tubing on the utility poles. In Tenafly, the markers are made of dark material, and so are less visible. “There’s no PVC pipe in the Torah,” he said.

Another resident said: “This isn’t about religion. This is about real estate in town. Look north to Monsey. They’re not putting money into infrastructure, into schools and parks.

“That’s not American,” he said.

Another resident offered the suggestion that the town look into moving utility wires underground. That would prevent power outages during storms — and not give the eruv a pole to stand on.

Later that week, in a phone interview, Mr. Rosen talked more about the eruv.

“Tenafly was different,” he said. In that case, the eruv supporters argued that because the town allowed its poles to be used for all sorts of notices, “like at Christmastime, when they put up posters to encourage people to shop at downtown merchants,” it therefore was illegal to keep them from putting up eruv markers. That argument does not apply in Upper Saddle River, he said. “There are a lot of different issues here.” Still, overall, “there is a feeling that to the extent that courts have decided this,” the decisions have been in favor of eruvs.

But, Mr. Rosen said, in this case, “Upper Saddle River is intent on preserving its rights regarding its poles.” He’s still working out the facts of the case. There is, however, one thing that he already does know. “The opposition to the eruv absolutely is not based in anti-Semitism,” he said. “There are many Jews in Upper Saddle River who oppose it.

“I won’t stand for anti-Semitism. The town issued a statement that it will not stand for it. No one will stand for it.

“There were 200, maybe more than 200 people at the meeting on Thursday night,” Mr. Rosen continued. “The most amazing part was at the end, when a Holocaust survivor came up to speak. You could have heard a pin drop in the room.

“There were a couple of boisterous anti-eruv supporters sitting there, and they shut up. They all listened to him preach for harmony. It was a poignant moment.”

(The Wiesenthal Center’s Michael Cohen contested Mr. Rosen’s memory. “They let the Holocaust survivor speak, but they were heckling him,” Mr. Cohen said. “They actually heckled a Holocaust survivor.)

“There are some important legal issues here,” Mr. Rosen concluded. “But it is not about anti-Semitism. There are Jews on both sides.”

Noah Feldman is a professor at Harvard Law School; he represented Tenafly, pro bono, in its fight against the eruv. It’s an issue he feels deeply about — his passion then, a decade and a half ago, as he discussed why an eruv on municipal poles was a breach of the division between church and state, had been palpable. But now he is resigned to the other side’s victory.

“At this point, it seems pretty well established that if religious Jewish communities want to erect eruvim” — the plural of eruv — “and do so in a way that doesn’t put an external cost on the town, they can do so,” he said. “There aren’t too many legal options available to a town that says, ‘We really don’t want an eruv here.’”

He said that the ruling against Tenafly established “that if the town had ever allowed any deviation from its existing regulations, they would have to allow lechis.” (Lechis are the vertical markers that represent the sides of a doorway.) “To fail to do so would be treated as a form of discrimination and a violation of the Free Exercise clause of the Constitution,” he said.

“By contrast, the position in the Hamptons case was that allowing an eruv to be erected was itself a violation of the Constitution’s establishment clause,” he continued. “It would have barred the use of town property for an eruv.” Instead, “the court held that it does not violate the establishment clause to allow town property to be used by the eruv.

“Add to that the appointment of Justice Neil Gorsuch, a strong religious freedom advocate, to the Supreme Court, and I think the atmosphere is very positive for eruvim in the U.S.”

Dr. Feldman said that there are some “tricky aspects” of eruv law that have yet to be discussed by a court.

“In order for an eruv to be halachically valid, it needs a form of authorization, a kind of effective rental right from the town, which has to be paid for,” he said. The Second Circuit court, which ruled on the Hamptons eruv, “didn’t focus on that.”

If it had, there might have been a different result — or perhaps the eruv supporters would have won anyway. “In the current legal environment, most likely the court would hold that does not violate the establishment clause,” he said.

“There will always be some political sentiment, some homeowner sentiment, that’s worried about demographic changes,” he said. But passing laws to prevent demographic changes — particularly those involving religious or racial groups — “are typically unlawful under the Fair Housing Act. Unlawful and unconstitutional.”

Reaction from the official Jewish world has been cautious and measured.

Jason Shames

Jason Shames

Jason Shames, the CEO of the Jewish Federation of Northern New Jersey, whose catchment area includes the Bergen County towns, is in Israel now, so his reaction necessarily was constrained by his circumstances. He has been worried, though, by some of the anti-Semites who have been drawn out of their underground lairs by this controversy, more or less as rain draws worms out from their holes.

“Hate speech should never be accepted,” he said. “But I am concerned about overstating the anti-Semitism, given people’s real concerns.”

Gary Siepser is the CEO of the Jewish Federation of Rockland County, which includes Monsey.

“Every person who has an opinion on this filters it through their own lens, their own life experiences, their own belief systems, and every person perceives it differently,” Mr. Siepser said. “The big mistake anyone makes is in lumping anyone together on either side of the multiple sides of this question.

“We see bigotry when people make assumptions about ‘the other,’ whether that other is a chasid or people who follow other Jewish practices or people from other faith traditions. Everyone sees it differently. The problem is when you make assumptions about other people’s belief systems and motivations and intentions.

“It’s a big mistake to make assumptions. We live in a very complicated world.”

To be more specific, Mr. Siepser concluded, “the federation’s position is that putting up an eruv is a complex question of zoning, land use, planning, rights of way, and municipal authority,” he said. “There are a lot of moving parts, and at the end of the day this will be decided by the courts — and that is the proper venue for this to be sorted out.”

Steve Gold of New City is the chair of Rockland’s Jewish Community Relations Council.

The local newspapers ran stories on their websites, and town-centered Facebook groups debated the eruv. All those stories and groups attracted anti-Semitic comments, he said, but “I think that those websites blew this out of proportion. They made it seem like it was all about exclusion, but it had nothing to do with that.

“I think that the rhetoric is intense and over-exaggerated,” he continued. “As long as the people putting up the eruv abide by the laws and zoning regulations, it should not be an issue.

“I see nothing wrong with people putting things on poles. It’s the same as people putting Christmas lights on poles. As long as it abides by zoning regulations, no one can stop them.

“It’s the same thing with political posters. My neighbors might not like the judge whose poster is on my lawn, but it’s my right to do it.

“I think that people believe that the Orthodox can do whatever they want to do, without asking anybody, and that’s not true.

“These Facebook pages — they are riling the base. The base responds, and it responds disgustingly. They will call people roaches and skunks, and say that they need to be exterminated. The people running the Facebook pages say that they can’t monitor everything, all the comments, but if you want to be a responsible Facebook host, you have to monitor what people are saying.”

The question of how to monitor Facebook comments about explosive local issues may be fairly new, but the underlying problem is not, Mr. Gold said. “It reminds me of the civil rights struggles of my childhood. If a black family would move in — Oh my God! That is what I feel this to be.

“This is discrimination. If you abide by the rules and regulations — this is America. You can do what you want. And then people have the right to complain and protest about it. This is America!”

Michael Cohen added that one of the Facebook groups, Mahwah Strong, drew so many anti-Semitic comments that its own founder resigned from it. “He said that was not at all what he wanted, and that the anti-Semitism has gotten out of control.”

Mr. Cohen also said that he is struck by how few of the people who loudly protest the eruv actually know what it is.

Rabbi Elchanan Weinbach, the Yeshiva University-ordained leader of Congregation Shaarey Israel in Montebello, next door to Monsey, understands what an eruv is; he explained its function as it is commonly understood in the Orthodox world.

Rabbi Elchanan Weinbach

Rabbi Elchanan Weinbach

An eruv is a boundary that encloses a domain. On Shabbat, carrying from an enclosed domain to a public domain, from a public domain to a private one, or within a public domain all are prohibited.

That sounds straightforward, but the terms demand explanation. “The terms private and public are very fuzzy,” he said. “It is not about ownership. It really means enclosed as opposed to unenclosed. Carrying from one to another, or carrying in an unenclosed domain for more than six feet, is a violation.”

Sounds — clear, right? Maybe not so much.

“What if you are in your home, and someone opens the door?” he said. “Are you no longer in an enclosed domain? No, you are still in an enclosed one, because the rule is that the shape of the doorway is considered as if it were an actual mechitzah — a partition. If you still have the shape of the doorway, you’re okay.

“So from here, if you can string together enough doorways, you can enclose a large area. And that’s what an eruv does. That’s why they put strips on them. They primarily are markers. The wires form the lintel as the top of the doorway. Once you have the outline of a doorway, that becomes an abstract partition.”

So an eruv, made of these abstract shapes of doorways, can enclose a domain and make it private, and therefore allow observant Jews to carry objects on Shabbat. That’s very abstract. It’s symbolic, isn’t it?

No, Rabbi Weinbach said sharply. “You cannot use the word symbolic in Jewish law. This actually functions in a concrete way, as a partition. It is not symbolic. It is designated. I prefer to say that it is a designated doorpost and lintel.”

Of course, this can be hard to explain to non-Jews, property owners within the eruv, who hear about the eruv and assume that it means that their property somehow has become less theirs. It hasn’t. But those property owners’ misapprehension also is an intuitive one, and the idea that the word symbolic cannot be used to explain the eruv makes that explanation even harder to get across. From their point of view, it is symbolic; were it not symbolic, it would never be approved.

The term “legal fiction” is another source of understandable friction between the observant Jewish world and everyone else. “It is not a legal fiction,” Rabbi Weinbach said. “It is a legal reality within Jewish law.”

Outside Jewish law, he conceded, the concept could go far in explaining the eruv’s irrelevance to other people’s property ownership.

There is a detail about the Mahwah eruv that gives him pause. “My understanding is that some enterprising people built an eruv without asking permission to put strips on poles.” It was not done in secret, but without clear approval from the town. “You can’t have an eruv without the agreement of whoever owns the street,” he said. “That’s why every eruv rents the streets for it. I don’t understand what they were thinking, because an eruv wouldn’t work anyway without township approval.”

As much as Rabbi Weinbach cares about the laws of eruvin, he thinks that this debate at its core is not really about an eruv. It’s about chasidim; about Monsey; at its deepest level, it’s about home.

“This is not about anti-Semitism,” he said. “There are many Jews in Montebello, and in Mahwah and Upper Saddle River. They’re happy living there. There are synagogues.

“This is not anti-Semitism,” he repeated. “If you have to give it a label, it’s anti-chasidim.

“That’s because everyone in Rockland County and surrounding areas understands that when chasidim move to a community, they have to move en masse. That’s because they need, for example, 10 men for a minyan. They need services — stores, schools — and when they come, they can change the character of our neighborhood.

“In our very progressive world, nobody cares about that. What concerns them is that the history of chasidim moving into an area is that they ignore building codes, which sometimes means that they will just built additions and pay the $10,000 fine. There is a tendency to build multifamily homes where they aren’t zoned. And there is a social tendency to behave in a fashion that is not in sync with the common feel of an American neighborhood. They isolate themselves.”

Often, Rabbi Weinbach continued, residents say that they don’t want their neighborhoods to change. Their reaction to news that chasidim are moving in, he said, quoting them, is, “‘I have been living here for 30, 40, 50 years. I love my community. I have no objection to anyone of any race or any religion moving in, but if they are going to change the character of the community I have invested in — as they have done, for example, in Spring Valley, in Monsey, in Airmont — that means that everybody there now is going to sell, and it will become all chasidic. I don’t want that.’”

There are other problems, he said. “The school board. Everyone here knows that the chasidic community has consciously taken over school boards and used the budgets in their favor, to the great disadvantage of the members of the community who use the public school system as their main educational option. These are the children of immigrants, who now are getting just a bare-bones education.

“So, for example, take the East Ramapo school district. They have destroyed it. There is no other word for it. I could use harsher words for it, though…

“The chasidim also will take over the zoning boards, and once they have control of the school board and the zoning board, then the quality of life will decline, and everyone who is not chasidic will want to leave.

“So if I live in Mahwah, say, and I love Mahwah, and I have been living there for 40 years, and I know everyone by name, and I know all their kids’ names — well, that’s the end of that.”

Is any of this feeling anti-Semitic? No. It is not. “It is rooted in the radical transformation in the quality of life that chasidim have brought with them when they have become the dominant group, in town after town. This is not anti-Semitism.

“I have congregants who live in Mahwah. No one gives them a hard time. No one cares if they are Jewish. What they care about is people who come en masse and build multifamily homes that destroy quiet neighborhoods. Why should I allow that?”

Rabbi Weinbach grew up on Long Island’s South Shore, in Woodmere. It was an Orthodox community, but there was no eruv. For men, it wasn’t a big deal, he said. “We just didn’t carry on Shabbat.

“It’s very disadvantageous for women,” he added. To push a stroller is to violate the halacha of Shabbat, “so until their children can walk, women are trapped,” he said. His children, who now are adult, always have lived within an eruv, but there is not one in Montebello. “It doesn’t affect us now, but as we look to grow the community, we want to attract young families who are observant. It will be very difficult in the absence of an eruv.”

Still, knowing that — that his own community will need an eruv if it is to grow — does not affect his view of the eruv proposed for the towns of northern Bergen County. “This is not about an eruv,” he said. “This is about chasidism radically altering the quality of life in the community.”

The battle over the eruv will continue. All we can predict definitively is that it will be ugly. All we can hope is that it will end with reconciliation brought about by greater understanding of the complications of the relationships between synagogue and state, religion and politics, community and polity, and in the end, inevitably, invariably, between Jew and Jew.