“It’s an Israeli-American agreement that has nothing to do with peace,” she said.

Mr. Netanyahu and Mr. Trump were primarily trading Palestinian rights to distract from their legal troubles — Mr. Netanyahu’s pending criminal charges and Mr. Trump’s Senate trial — and to improve their chances of re-election, she said. “In the longer term, the other strategic objective is to deliver Palestine to the Israelis,” she added.

Mr. Netanyahu told Israeli reporters in Washington that his cabinet would vote on the measure on Sunday. The decision could still be subject to legal challenges because the current cabinet is an interim government.

Israeli leaders, including Mr. Netanyahu, had refrained from extending Israeli law anywhere in the West Bank for decades, fearing international sanctions. Most of the world considers Israeli settlements there illegal.

But Mr. Trump’s green light came with a promise to veto any such moves against Israel by the United Nations Security Council, Mr. Netanyahu indicated to Israeli reporters.

For Mr. Netanyahu, who is battling for his future after being charged in three corruption cases, annexation offers the opportunity to lay down a legacy beyond being the country’s longest-serving prime minister and the first sitting one to be indicted.

Mr. Netanyahu’s challenger, Benny Gantz of the centrist Blue and White party, has opposed any unilateral annexation and has said that there is no rush to annex territory until after the March 2 elections.

His party issued a statement Tuesday hailing Mr. Trump’s plan as “historic” and calling it “entirely consistent with the principles of state and security” espoused by the party.