Since last month’s cease-fire, Gaza has been divided by a yellow line splitting Hamas-controlled Gaza to the west from Israeli-occupied Gaza to the east. At first, the line was invisible. But after Israeli soldiers repeatedly opened fire on Gazans who crossed it, Israel began to give the line a physical dimension with yellow concrete blocks. Now a U.S.-backed plan designed to house thousands of Palestinians on the Israeli side of the line could make the separation more prominent and, some fear, more permanent.U.S. officials call the new developments Alternate Safe Communities. The initiative is designed to create communities of vetted Gazans, but it would separate them from those on the Hamas-controlled side of the yellow line, where the large majority of people in Gaza live, an official in Israel and a State Department official familiar with the planning told me.Lieutenant General Patrick Frank—the military lead coordinating efforts to implement President Donald Trump’s peace plan—recently told colleagues that each settlement should include a medical center, a school, an administrative building, and “temporary housing for approximately 25,000 people,” according to an email I reviewed that has not been previously reported on. He emphasized the urgency of moving ahead with the plan, the email said. A senior Trump-administration official confirmed to me that at least one pilot Alternate Safe Community will be built. The first site being eyed for development, in the south of Gaza near Rafah, is very likely owned by Palestinians, as are the other potential sites, of which there are many. The senior administration official couldn’t immediately say if the United States knows who owns the property on which the pilot community will be built.[Read: Food aid in Gaza has become a horror]Only Palestinians approved by Israel’s domestic intelligence agency will be permitted to move in. It remains unclear what the criteria will be for approval, although whether a person or their relatives have ties to Hamas would be a starting point, the official in Israel with direct knowledge of the plan told me. Fewer than 2 percent of Gaza’s 2 million residents are estimated to live on the side of the line controlled by the Israel Defense Forces, according to the official in Israel.Step one in establishing a new community in Gaza will involve clearing unexploded ordnance and rubble. The State Department has awarded a contract to Tetra Tech, a U.S.-based engineering firm, which is expected to prepare the ground for the first Alternate Safe Community, the State Department official told me. The company’s chief executive attended meetings yesterday in Israel with others involved in implementing the peace plan, two people familiar with the matter told me. Tetra Tech didn’t respond to a request for comment.Trump’s top Middle East envoys, his son-in-law Jared Kushner and his close friend Steve Witkoff, support the idea of the housing initiative, as does the Israeli government, two people familiar with the matter told me. (A spokesperson for the Israeli government did not comment.) But the plan has caused a backlash from some officers in the State Department, as well as from foreign governments and aid organizations. The objections are partially rooted in the restrictions the new development could impose on Palestinians who sign up. The branch of the Israeli military that controls humanitarian border crossings into Gaza has told U.S. officials that civilians let into the developments will not be allowed to cross back into the half of Gaza that Hamas controls, according to the two officials. State Department aid experts in Israel are “advocating for ensuring freedom of movement across lines,” according to the email I reviewed. It seems likely that the communities “would be a place where people are effectively sequestered, although they wouldn’t use those terms,” the State Department official told me.[Read: Israel’s last chance]Under Trump’s plan, the yellow line is supposed to disappear once the IDF hands over the land it controls to a still-to-be-established multinational force. Hamas is also meant to relinquish its control. And the Alternate Safe Communities are themselves intended to be temporary. But the Middle East is etched with partitions that were designed as interim measures but became permanent fissures. People who question the new plan say that, by preventing Palestinians from moving freely in relative peacetime, it risks creating an enduring divide down the middle of Gaza. One U.S. official told The Atlantic that the program is an experiment in providing Gazans with safe housing beyond Hamas’s control.The idea of Alternate Safe Communities, or something like them, has percolated among top U.S. and Israeli officials for a while. After a cease-fire and an exchange of hostages was agreed upon as the first phase of Trump’s peace plan, the U.S. set up the Civil-Military Coordination Center in Israel to support next steps. The plan for Alternative Safe Communities was presented the day the center opened, the official in Israel said.Among the many challenges confronting the center is meeting the needs of the many Palestinians displaced by the devastation of two years of war. “You see these people moving back,” Kushner told CBS’s 60 Minutes, describing a recent tour of Gaza. “It looked almost like a nuclear bomb had been set off.” Kushner asked the Israeli soldiers facilitating his tour what these people would do. The soldiers, he says, replied: “They’re going back to the areas where their destroyed home was, onto their plot, and they’re going to pitch a tent.”[Photos: Gaza’s starvation and chaos]The Alternate Safe Communities plan is seen by Trump officials as a better solution, and the White House has been driving the project. Kushner made clear in a press conference in Israel last month that “no reconstruction funds will be going into areas that Hamas still controls.” He discussed the construction of “a new Gaza” on the Israeli-held side instead: “to give the Palestinians living in Gaza a place to go, a place to get jobs, a place to live.” Earlier this year, Trump said he wanted to see all Palestinians forced out of Gaza so the U.S. could run the area as “the Riviera of the Middle East,” though he has since backed away from that.Plans for the housing sites remain fluid: The number of Palestinian occupants expected to live in each new community changes almost by the day, according to the official in Israel. A team of U.S., U.K., and Israeli military officials working on the project has already revised the intended occupancy of each community down to about 6,000, from an original estimate of 25,000. The senior administration official wrote to me that “all of these details are being considered and plans are still being discussed on how to best provide Gazans with safe temporary housing.”Others involved in post-cease-fire planning for Gaza say they worry about the implications of any approach that excludes the many Palestinians on the other side of the yellow line. Hamas has run Gaza for nearly two decades, and many Gazans have connections to the militant group. What will happen to Gazans who fail Israel’s background check is unclear, the official in Israel told me. The ultimate result of the Alternate Safe Communities plan, the official worries, might be “a population that you move, and you say that they are good and safe, and then another population that is apparently all Hamas, so then whatever happens in that area is justified.”What is not in doubt is that Gaza needs more places for people to live. About 7,400 tents have been let into Gaza through the United Nations’ aid-coordination system since the cease-fire began, according to the Norwegian Refugee Council, which is part of the assistance effort. But 1.5 million people need emergency shelter. Their homes are damaged, destroyed, unreachable, or beyond the yellow line.The plan for Gaza carries some echoes of another advanced decades ago by the United States. During the Vietnam War, the U.S. government funded and supported a plan by the South Vietnamese to relocate rural peasants to “strategic hamlets” to isolate them from the influence of communist insurgents. The U.S. and the South Vietnamese were convinced that they would win the peasants’ support by improving their quality of life with access to medical care and schools. But the residents were miserable. And separating the insurgents from the civilians proved far harder than expected; a communist agent was accidentally made the overseer of the entire program. Roger Hilsman, then the assistant secretary of state for East Asian and Pacific affairs, ultimately called the effort “worse than useless.”Before anyone moves into an Alternate Safe Community, those in charge of deciding Gaza’s future still have to resolve a number of serious questions. A U.S. official acknowledged, for instance, that Palestinians may be reluctant to move in as long as the IDF is in charge. It is also unclear how safe passage across military lines will be ensured for vetted Gazans who want to move in. The military officials working on the plan initially envisioned a new settlement operating by next month, the source in Israel said, but that timeline is now uncertain.A plan to transition control from the IDF to a multinational force on the Israeli side of the yellow line hasn’t made much headway, in part because neither Israel nor Hamas has approved the peace plan beyond the cease-fire. The cease-fire itself has been marked by intermittent violence, and Hamas has killed Palestinians that it claimed were collaborating with the Israelis.Israeli Prime Minister Benjamin Netanyahu has told his cabinet that Israel will hold veto power over which countries join the multinational stabilization force. Candidate countries, meanwhile, may reconsider their possible involvement if they oppose the Alternate Safe Communities plan. The idea of relocating Palestinians to housing on the Israeli side of the yellow line has alarmed European, Arab, and Muslim governments, according to the Financial Times; one Arab diplomat told the publication that “there is a clash coming on this between Palestinians, Egyptians, many others, Qataris, Turks and the US and Israel if the US continues to support the Israeli point of view on this.”Trump has put the onus on “Muslim and Arab nations” to finance the rebuilding of Gaza, but so far, none seems to have agreed to back the housing construction. The State Department currently plans to pay an aid organization to provide basic services in the new communities and to use an existing contractor to manage them, the State Department official said.The peace plan also foresees day-to-day operations in all of Gaza being taken over by a “technocratic, apolitical committee of competent Palestinians from the Strip,” according to Trump’s plan. But when it comes to the Alternate Safe Communities plan, the official with direct knowledge of the plans told me, “it’s unclear if there was any consultation at all with any Palestinian.”