During the first ten months of the Trump Administration, the top Palestinian diplomat in Washington, Husam Zomlot, was summoned to the White House every two or three days, he told me. He spent many hours with Jared Kushner, the President’s son-in-law and lead peace negotiator, working on Trump’s ambitious plan to end the conflict between Israel and the Palestinians. For the Palestine Liberation Organization’s mission in Washington—it’s not technically an embassy, since it does not represent a state—it was the highest-profile engagement with American officials since the office opened, in 1994. In conversations we had during those first months, Zomlot was ebulliently optimistic, despite seven decades of hostilities, about achieving peace.

No longer. In the third blow this year to the peace process—and the one that may well doom it—the Trump Administration on Monday ordered the P.L.O. to shutter its diplomatic mission in Washington, a dark red-brick building on the edge of the trendy Georgetown neighborhood. The move will eliminate a communication channel—diplomatically and physically—that has been at the heart of the peace process under four Administrations. It’s basically a punishment. The State Department cited the Palestinian failure to “advance the start of direct and meaningful negotiations with Israel” as the reason for the closure. It also accused P.L.O. leaders of condemning “a U.S. peace plan they have not yet seen” and said that they “refused to engage with the U.S. government with respect to peace efforts and otherwise.”

Determining blame for the undermining of one of the President’s most ambitious foreign-policy goals is, at the least, a chicken-and-egg argument. Despite the State Department’s claims, the Administration is not blameless. In December, 2017, following through on a campaign promise, Trump recognized Jerusalem as Israel’s capital—even though the Palestinians have claimed part of the city as their capital, too—which led the Palestinian Authority to cut off diplomatic talks. The formal opening of the U.S. Embassy in Jerusalem, in May, led the Palestinian Authority to recall Zomlot from Washington.

In the past month, the Administration has also severed aid—directly and through international organizations—that has an impact on millions of Palestinian lives. It cut off some two hundred million dollars to bilateral aid projects—for economic development, democratic reforms, health care, education, security, and humanitarian issues—to Palestinians in the West Bank and Gaza. It also stopped providing three hundred million dollars in U.S. aid to the U.N. agency that supports 5.4 million Palestinian refugees scattered across the Middle East, calling the program “irredeemably flawed.” The U.S. accounted for nearly a third of the agency’s budget.

The accumulated impact of these moves may kill off a peace process that, last year, Trump bragged was “not as difficult as people have thought.”

The Palestinians responded to the closure of their mission to Washington with outrage. I reached Zomlot by phone on Monday, in Ramallah, the West Bank capital, in between crisis meetings with the Palestinian leadership. He had been notified of the closure in a telephone call from the State Department, followed by a formal letter. “The peace process as we knew it has definitely just received a lethal bullet to its heart,” he told me. “This Administration is using bullying as a tactic and trying to blackmail us.” He called the U.S. announcement “a reckless act in blind execution of Israel’s wish list that started with Jerusalem.”

In a statement announcing its decision, the Administration said that it “continues to believe that direct negotiations between the two parties are the only way forward.” Kushner’s long-overdue peace plan is still expected to be rolled out this fall, although it has been deferred repeatedly, without explanation. On Monday, the State Department warned Palestinians against responding to the latest U.S. ruling with violent protests. “This action should not be exploited by those who seek to act as spoilers to distract from the imperative of reaching a peace agreement,” Heather Nauert, a State Department spokesperson, said, in a statement. “We are not retreating from our efforts to achieve a lasting and comprehensive peace.”

Former U.S. diplomats reacted with skepticism. “How absurd,” Daniel Kurtzer, a former U.S. Ambassador to Israel, who now teaches at Princeton University, told me. “The so-called peacemakers in this Administration have turned mean and punitive—cutting funding for a Palestinian hospital and Palestinian education and social services, and now shutting down communications between Palestinians and the American people. Shame on our officials.”

Prospects for the Trump peace plan were already bleak. A joint survey of Palestinians and Israelis released last month found that only forty-three per cent on both sides of the conflict still support a two-state solution. More ominous, a poll of Palestinians this summer found that “a large minority supports return to an armed intifada,” with a more general “rise in support for popular resistance.” The first intifada—which raged sporadically from 1987 until the signing of the Oslo Accord, in 1993—led to the emergence of Hamas, a militant Islamist political movement that won the 2006 legislative election and now rules in Gaza. More than a thousand Palestinians died in the violence during that time. The second intifada erupted in 2000 and lasted more than four years. An estimated three thousand Palestinians and more than eight hundred Israelis died. This spring, Palestinians in Gaza launched a six-week Great Return March along the frontier with Israel that led to clashes that killed dozens and injured thousands; it threatened to spark a third intifada.

The Trump Administration also tried to link its decision to close the P.L.O. diplomatic presence to the Palestinian application, in May, to have the International Criminal Court investigate Israel for war crimes and crimes against humanity, including targeting unarmed civilians with live ammunition during the Great Return March in Gaza. In his first major speech since becoming Trump’s national-security adviser, in April, John Bolton condemned the Palestinian appeal. “The United States supports a direct and robust peace process, and we will not allow the I.C.C., or any other organization, to constrain Israel’s right to self-defense,” Bolton said in the speech, on Monday, to the Federalist Society.

At the opening of the U.N. General Assembly next month, the Palestinian President, Mahmoud Abbas, reportedly plans to appeal to the world body to upgrade the Palestinian Authority’s status from “observer” to full member. Abbas would need support of nine of the fifteen members of the Security Council to move forward, but the effort will almost certainly be vetoed by the United States.

Zomlot told me that the Palestinians—under growing pressure from Trump to comply with whatever Kushner’s still-secret plan entails—are turning to the international community to fill the vacuum. “We are standing firm,” he said. A statement issued on Monday by the P.L.O. mission in Washington, possibly its last, said, “While today is a dark day for peace in the Middle East, for multilateralism, and the integrity of the international political and legal system, we will continue our struggle to pursue all possible legal and political means to achieve peace, independence, and our international enshrined rights.” The prospects, however, look grim.