When President Trump hosted Prime Minister Benjamin Netanyahu of Israel at the White House in early April, a reporter reminded Mr. Trump that his 2024 campaign promise to end the war in Gaza remained unfulfilled.

Israel had recently broken a tenuous cease-fire in its 18-month war with Hamas and renewed its bombardment of Gaza. But Mr. Trump professed optimism.

“I’d like to see the war stop,” he replied. “And I think the war will stop at some point that won’t be in the too-distant future.”

One month later, prospects for peace in Gaza have dimmed even further.

Mr. Netanyahu warned on Monday of an “intensive” Israeli escalation in the Palestinian enclave after his security cabinet approved plans to call up tens of thousands of reservists for a fresh assault there.

Israeli hawks insist that only force can pressure Hamas into finally releasing the more than 20 hostages it still holds captive and end the conflict. But many analysts say a major Israeli escalation could kill any hope left for peace.

The question now is how Mr. Trump will react. Analysts said that, after an early flurry of diplomacy to free the hostages and reach a long-term settlement, Mr. Trump and his senior officials have grown distracted from the conflict. That has amounted to something of a free hand for Mr. Netanyahu, who appears prepared to use it.