BEIRUT, Lebanon — In unveiling his plan Tuesday for solving the conflict between Israel and the Palestinians, President Trump confidently declared that Arab countries would play a key role in its success.
But none of the United States’ Arab allies formally endorsed the plan or made concrete commitments to back it, raising questions about how helpful they will really be in bringing it to fruition.
Mr. Trump announced the plan in an appearance at the White House with Prime Minister Benjamin Netanyahu of Israel, describing it both as necessary for Israel’s security and as an opportunity for the Palestinians to govern themselves and grow their economy.
There are “many, many countries who want to partake in this,” he told Mr. Netanyahu, predicting that “you are going to have tremendous support from your neighbors and beyond your neighbors.”
But clear indications of that support were lacking.
While three Arab ambassadors — from Oman, Bahrain and the United Arab Emirates — were present at the announcement, Mr. Trump said, there were no Palestinians.
“You couldn’t find a single Palestinian to attend?” asked Daoud Kuttab, a Palestinian journalist and columnist with Al-Monitor, an online news site.
And despite Egypt and Jordan having peace treaties with Israel, and Mr. Trump having chosen Saudi Arabia for the first overseas trip of his presidency, “none of them came,” Mr. Daoud noted.
For decades, the Palestinian cause was that rare issue that united Arabs across the Middle East. But in recent years, it waned in importance as the peace process foundered.
Some Arab leaders turned their focus inward to domestic security and economic problems. Others, including Persian Gulf nations such as Saudi Arabia and the United Arab Emirates, have come to see Iran as the region’s greatest threat, and Israel as a potential ally against it.
Concerns about Iran had become “much more existential than the Palestinian issue,” Mr. Kuttab said. “They are worried about their physical presence being threatened from Iran, much more than Israel,” he said.
Still, for all the changes, Arab leaders refrained from publicly backing Mr. Trump’s plan.
In his address at the White House on Tuesday, Mr. Trump thanked Oman, Bahrain and the United Arab Emirates “for the incredible work they’ve done in helping us with so much,” and noted that their ambassadors were in attendance. But even those countries did not formally endorse the plan.
Some other countries took a notedly measured stance.
The foreign ministry of Egypt, the first Arab country to reach a peace treaty with Israel, praised Mr. Trump’s efforts to reach an agreement, but the language of its statement remained inside the boundaries of Egypt’s longstanding policy on the conflict.
Egypt “appreciates the continuous efforts” of the Trump administration to end the conflict, the statement said. It encouraged both sides to resume talks that might eventually restore to Palestinians their “full legitimate rights through the establishment of a sovereign independent state.”
The carefully worded statement was a clear expression of support for the American president, if not for the plan itself, from Egypt’s authoritarian ruler, President Abdel Fattah el-Sisi, whom Mr. Trump once called “my favorite dictator.”
The Trump administration is currently mediating a dispute involving Egypt by hosting negotiations with officials from Egypt, Ethiopia and Sudan over a contentious $4 billion dam that Ethiopia is building.
Jordan, another American ally that has made peace with the Jewish state, effectively ignored Mr. Trump’s plan and restated its commitment to many of the Palestinian demands that the White House proposal disregarded. Among them: the general borders of a Palestinian state with a capital in East Jerusalem.
In a statement, Foreign Minister Ayman Safadi said Jordan would continue to work with Arab countries and the international community for “the achievement of a just and lasting peace that meets all the legitimate rights of the Palestinian people.”
Saudi Arabia, too, praised Mr. Trump’s efforts, but did not endorse his plan. The kingdom stuck to its longstanding stance that negotiations should lead to “an agreement that achieves legitimate rights of the Palestinian people.”
The de facto ruler, Crown Prince Mohammed bin Salman, has broken with previous Saudi leaders by speaking of Israel’s right to its own land and by praising its economy. But Prince Mohammed has not taken formal steps to improve relations because of potential blowback from his own population.
As American allies reacted cautiously to the proposal, adversaries heaped scorn on the United States for its support for Israel.
Hezbollah, the Lebanese militant group and political party, called Mr. Trump’s plan “the deal of shame” and pointed an accusing finger at those Arab countries that have allied themselves with the United States.
“This deal would not have taken place had it not been for the complicity and betrayal of a number of Arab regimes, secretly and publicly involved in this conspiracy,” it said in a statement.
In much of the Arab world, Mr. Trump’s proposal was variously received with outrage, humiliation or weary resignation. Hostility toward the Americans and Israelis appeared matched only by a sense of disillusionment among some Arabs toward their own leaders.
“Historical farces are repeating themselves,” Gamal Eid, a veteran human rights activist in Cairo, said on Twitter. “From the miserable 1917 Balfour Declaration to the farcical 2020 Trump Declaration. And Arab leaders are either useless or cheering.”
Nabil Fahmy, a former foreign minister of Egypt, said he feared that Mr. Trump’s proposal would not only fail to bring peace to the region, but that it might also scupper the chances for a lasting deal.
“To put the proposal this way, you must want to have it rejected,” he said. “And if you reject this deal, you are destroying the tenets of the peace process and all possibilities for progress. It is just astonishing.”
Ali Shihabi, a commentator close to the government of Saudi Arabia, said the plan was “all downside and no upside for U.S. allies in the region.”
Paula Yacoubian, a member of the Lebanese Parliament, was equally dismissive. “A deal from one side is the joke of the century,” she said on Twitter.
Mohamed ElBaradei, a former vice president of Egypt, said he felt the same sense of shame and humiliation that followed the defeat in the 1967 Arab-Israeli war. “How would we justify this miserable state of affairs to the upcoming generations?” he wrote on Twitter.
For many, the Trump proposal marked another dismal milestone in what many Arabs view as America’s decades-long abandonment of the Palestinian cause.
A thread of mournful, broader regret ran through some of the commentary, too, a sense that a cause that had united the Middle East for decades was quietly fading away, losing its relevance, and that ordinary Arabs were simply losing interest.
Some said young Arabs were simply preoccupied by the violence or political turmoil that followed the 2011 uprising in several countries, or had themselves been silenced.
“If the governments of the region were representing the will of their people, then perhaps Arab voices would be louder,” said Timothy E. Kaldas, a Cairo-based analyst with the Tahrir Institute for Middle East Policy. “But with the extraordinary repression the region has seen, with regimes uninterested in critical conversations in their own countries, it’s very hard to see what the publics in those countries could actually do.”
Ben Hubbard reported from Beirut, and Declan Walsh from Cairo. Nada Rashwan contributed reporting from Cairo.