But far from a bold effort to bring old enemies together — one that demands painful concessions from both sides — Middle East experts now expect the plan to be mainly a booster shot for Mr. Netanyahu’s desperate campaign to stay in power.

Benny Gantz, again Mr. Netanyahu’s rival in Israel’s third election in less than a year, will have his own separate meeting with Mr. Trump on Monday. He had at first resisted the invitation, fearing a political trap in which Mr. Netanyahu would get to play the statesman while Mr. Gantz would look puny by comparison. But analysts said he could not afford to snub the president, given Mr. Trump’s enduring popularity in Israel.

The Palestinians, who stopped talking to Mr. Trump after he ordered the United States Embassy to be moved to Jerusalem from Tel Aviv in December 2017, will not be at the White House to be briefed on the plan. They have vowed to reject it.

“For him to do this in the middle of an Israeli election, without any Palestinian participation and with no intention to follow up with any of the participants, shows this is not a peace plan at all,” said Martin S. Indyk, who served as special envoy for Israeli-Palestinian negotiations under President Barack Obama.

“It is a farce from start to finish,” he said.

Mr. Indyk’s verdict is harsh but not uncommon among diplomats who have worked on past peace efforts. Like other veterans of those fruitless negotiations, in both Democratic and Republican administrations, Mr. Indyk watched the early days of Mr. Trump’s diplomacy with fascination and even muted hope — that this most undiplomatic of presidents might achieve a breakthrough where they had failed.