Now, the attitudes and methods of West Bank settlement are inevitably leaking back across a border that Israel does not even show on its maps.

In 1996, the former Israeli chief rabbi Mordechai Eliyahu and his son Shmuel Eliyahu established a project to place “core groups” of their followers in depressed Jewish towns. The Eliyahus assigned their first core group to Acre.

Their goal was to bolster religious education and build faith-based charities. The elder Eliyahu, now deceased, was a pre-eminent teacher of the pro-settlement religious right. His son recently gained notoriety for issuing a religious ruling forbidding Jews to rent or sell real estate to non-Jews anywhere in Israel.

The group’s rabbi, Nachshon Cohen, was an alumnus of a yeshiva in the Palestinian city of Hebron. The reason to start the religious project in Acre was “the demographic problem,” Rabbi Cohen explained to me. The mixed city had about 45,000 residents. But Jews were leaving because “people didn’t want to live next to Arabs.” The energy of the new core group, Rabbi Cohen hoped, would keep the town Jewish.

A key part of the settlement project in Acre was the establishment of a hesder yeshiva — a seminary mixing religious study and army service. It, too, would help draw Jews who were both “ideological” and “on a high socio-economic level” into the town, the yeshiva’s director, Boaz Amir, told me. While moving back into Israel and speaking of helping poor Israelis, the settlers were reimporting the message of Jewish-Arab struggle. It was gentrification with a hard ethnonationalist edge.

Acre is just one of the mixed Jewish-Arab cities that religious nationalists have set out to “save.” The Acre core group has grown to 110 families, roughly one percent of the town’s population. Drawing this number of potential settlers to live inside Israel has an insignificant effect on settlement growth in the West Bank.

Yet it broadcasts a message that Israel’s Arab citizens are strangers and opponents rather than members of a shared polity. Rabbi Yossi Stern, the yeshiva’s dean, described the transformation of Acre’s Wolfson neighborhood — a set of Soviet-style apartment blocks built in the 1960s — from a Jewish to a majority-Arab area as “a national sin.” He argued forcefully that Jews should move back into such shifting areas. For Arabs and Jews “to be in the same neighborhood, in the same building ... that’s not good,” Rabbi Stern said. Coexistence was clearly not his goal.