“CLEARLY, there’s a war here, sometimes even worse than the one in Samaria,” the yeshiva student said. “It’s not a war with guns. It’s a war of light against darkness.”

We were sitting in the mixed Jewish-Arab town of Acre in Israel. The war he described was another front in the struggle he knew from growing up in a settlement in the northern West Bank, or Samaria: the daily contest between Jews and Palestinians for control of the land between the Mediterranean Sea and the Jordan River.

The explicit reason that his yeshiva had been established in Acre was to serve as a bridgehead in that struggle, just as West Bank settlements are built to bolster the Jewish hold on land there.

Israeli politicians and pundits labeled the Oct. 3 burning of a mosque in Tuba Zangaria, an Arab community in northern Israel, and the subsequent desecration of Arab graves in Jaffa as a sudden escalation. But they were mistaken.

For several years, extremist West Bank settlers have conducted a campaign of low-level violence against their Palestinian neighbors — destroying property, vandalizing mosques and occasionally injuring people. Such “price tag” attacks, intended to intimidate Palestinians and make Israeli leaders pay a price for enforcing the law against settlers, have become part of the routine of conflict in occupied territory.

Now that conflict is coming home. The words "price tag" spray-painted in Hebrew on the wall of a burned mosque inside Israel’s pre-1967 borders transformed Israel’s Arab citizens into targets and tore at the all-too-delicate fabric of a shared democracy.

Indeed, the mosque burning represented the violent, visible edge of a larger change: the ethnic conflict in the West Bank is metastasizing into Israel, threatening its democracy and unraveling its society.

The agents of this change include veterans of West Bank settlements seeking to establish a presence in shared Jewish-Arab cities in Israel and politicians backing a wave of legislation intended to reduce the rights of Arab citizens.

JEWS began settling in occupied territory weeks after the Israeli conquest of 1967. The strategy of settlement was born before Israeli independence in 1948, when Jews and Arabs fought for ethnic dominance over all of British-ruled Palestine. By settling the land, Jews sought to set the borders of the future Jewish state, one acre at a time. Post-1967 settlers, though they saw themselves as a vanguard, were really re-enacting the past, reviving an ethnic wrestling match — this time backed by an existing Jewish state.

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.

Segregation, though, is intrinsically a denial of rights. The countryside throughout the Galilee region of northern Israel is dotted with a form of segregated exurb, the “community settlement.” In each of these exclusive communities, a membership committee vets prospective residents before they can buy homes.

The concept, born in the mid-1970s, originally allowed West Bank settlers to ensure that their neighbors shared their “ideological-social background,” including the same shade of religious commitment. The Likud government that came to power in 1977 applied the model to create Jewish-only bedroom communities in the Galilee and in the Negev.

In 1995, Adel and Iman Ka’adan, an Israeli Arab couple, tried to buy a lot in the community settlement of Katzir. As educated professionals eager to live in a place with good schools for their daughters, they fit the community’s profile. But as Arabs they were ineligible. Their legal battle led to an Israeli Supreme Court decision in 2000 that rejected discrimination against Arab citizens, stressing, “equality is one of the foundational principles of the State of Israel.”

Katzir’s membership committee proceeded to turn the Ka’adans down again on the grounds that they would not fit in socially. It took five more years in court before they were they allowed to buy land there. But last April, the legislature overrode the judiciary, when the Knesset passed a law authorizing community settlements in the Galilee and Negev to reject candidates who did not fit their “social-cultural fabric.” The new law may not hurt the Ka’adans, but other Israeli Arabs will not be able to benefit from their Supreme Court victory.

That law is not an isolated incident. In its current term, the Knesset has sought to turn parliamentary power against democratic principles and Israel’s Arab minority. Foreign Minister Avigdor Lieberman’s far-right Yisrael Beiteinu party has led the offensive, but other legislators have joined it. Members of Tzipi Livni’s Kadima party co-wrote the community settlements law.

Another law makes it illegal to call for consumer boycotts of products from settlements. Other bills would require loyalty oaths to Israel as a Jewish and democratic state and to its flag and national anthem. They may never pass but they serve as political theater, labeling the Arab minority as disloyal.

Israel’s courts, human rights groups and large parts of the public have fought back, seeking to preserve the principle of equality and the fragile sense of a shared society. The problem they face is that Israel remains tied to the West Bank and the settlement enterprise. And the ethnic struggle cannot be kept on one side of an unmarked border.

If and when Israel finally leaves the West Bank quagmire behind, it will face a further challenge: the settlers need to be brought home. But allowing them to apply their ideology inside Israel, or to transplant whole communities from the West Bank to the Galilee, will only make the situation worse in Israel proper.

The reason for Israel to reach a two-state solution and withdraw from the West Bank is not only to reach peace with the Palestinians living in what is now occupied territory. It is to ensure that Israel itself remains a democracy — one with a Jewish majority and a guarantee of equality for its Arab minority.

Israel does not need to bring the war from Samaria home. It needs to leave that war in the past.