Far-fetched as Mr. Trump’s vision for Gaza may be — the Arab world has roundly rejected it and any forcible removal of a population violates international law — it abruptly shifted attention away from the future of the cease-fire deal, whose initial, six-week phase is due to end in early March.

US President Donald Trump said on Thursday Israel would hand over Gaza to the US after the fighting was over and the enclave’s population was already resettled elsewhere, which he said meant no US troops would be needed on the ground.