The defiant appearance of heavily armed Hamas fighters during Sunday’s handover to the Red Cross of three Israeli hostages held in Gaza since the 7 October 2023 terrorist atrocities was a sinister reminder, if one were needed, that the ceasefire deal negotiated last week hangs by a thread – and could snap at any moment.

The basic problem, going forward, is that neither Israel’s prime minister, Benjamin Netanyahu, nor Hamas’s reconstituted leadership, truly wants the truce to endure. Netanyahu was strong-armed, metaphorically kicking and screaming, into agreeing the deal by Donald Trump and his special Middle East envoy, Steve Witkoff.

For many months, Netanyahu, himself a hostage to far-right coalition allies, resisted the exact same proposals put forward last May by the then US president, Joe Biden. His possibly time-limited acquiescence now seems to be largely born of reluctance to rain on Trump’s inauguration parade in Washington.

Almost before the ink was dry, Netanyahu was reportedly reassuring disgruntled ministers that the ceasefire was temporary and that he had no intention of fully honouring its terms. He is said to have promised hardliners Itamar Ben-Gvir, who resigned in protest, and Bezalel Smotrich, who is threatening to do so, that he will soon resume the war.

The first phase of the ceasefire is due to last six weeks. Negotiations on the second stage, which calls for a full Israeli military withdrawal and the freeing of all living hostages in return for more Palestinian prisoner releases, must begin not later than 15 days from now. It’s doubtful they will get off the ground.

“Netanyahu has two ways to sink the agreement and find an excuse to renew the war. One option is to simply stall the negotiations for phase two … and waste time. He performed this same exercise several times to Biden’s team, which was too weak or unwilling to admit the reality of his sabotage,” wrote the Haaretz analyst Amir Tibon.

“The second option is to provoke an outbreak of violence in the West Bank. The tinder is already flaring there: extremist settlers set fire to homes and cars in several Palestinian villages on Sunday night, at the same time that millions of Israelis celebrated the return of the three hostages.”

West Bank violence, deliberately provoked or not, is but one possible trigger for a wrecking strategy. Netanyahu may claim that Hamas is not complying with the deal; he already did this at the weekend, delaying the start of the ceasefire by several hours. Sudden, random truce-rupturing clashes in Gaza and/or Lebanon are other possibilities to watch for.

Netanyahu faces a fateful choice in the next two weeks or so. By abandoning the ceasefire, he could appease the right, hold his coalition together, keep himself in power and head off inquiries into his pre-7 October policy of tolerating Hamas and his failure to stop the worst attack on Jews since 1945. If war resumes, he says he has Trump’s promise of unlimited weapons.

Or he could bet on peace, confront the far-right’s fury and risk the collapse of his government and early elections. Netanyahu might then be expected to campaign as the war leader who supposedly defeated Hamas, brought some hostages home, smashed Hezbollah in Lebanon and gave Iran a bloody nose, twice.

Since about 60% to 70% of Israeli voters are said to favour an end to the war, it’s possible that Netanyahu, breaking the habit of a political lifetime, may do the right thing. A lasting peace would win brownie points with the White House, clearing the decks for Trump to pursue his pet project: normalisation of Israel’s relations with Saudi Arabia and the consequent isolation of Iran by non-military means.

The trouble is, Hamas and the allied Gaza militants of Islamic jihad do not want the ceasefire to last, either. Its show of strength on Sunday, though very limited, sent a provocative message that Hamas has survived, that it still controls the remaining hostages and that there is, as yet, no successor authority in Gaza. In a statement on Monday, it vowed that Gaza “will rise again” – under its dubious tutelage.

There is a lot of talk about an Egypt and Qatar-backed interim administration of technocrats, about the Palestinian Authority (which notionally runs the West Bank) taking charge of Gaza. But right now, no one is empowered or ready to take over governance – and Hamas, by default, is filling the power vacuum. Netanyahu is partly to blame. He refused for 15 months to develop or discuss “day after” plans.

Looking ahead to the coming weeks, security inside Gaza could become a critical issue as tens of thousands of displaced and hungry people return to shattered homes and ruined neighbourhoods and start trying to reclaim their lives. Hamas will try to control aid distribution by the UN and allied agencies, just as it is controlling hostage releases through the Red Cross. This could cause deepening instability and rising internal strife.

Meanwhile, Hamas can be expected to quickly begin to rebuild its military capabilities, more determined than ever, after the drubbing it has received, to impose a terrible price on Israel – to whose destruction it remains pledged. “The footage of the Hamas fighters offered a stark reminder that the terror group remains in charge of Gaza,” the Times of Israel noted.

Israeli officials estimate only two of the group’s 24 battalions remain operational, the newspaper said. But it is reportedly regrouping under Mohammed Sinwar, the younger brother of Yahya Sinwar, the 7 October mastermind whom Israel killed last autumn. The outgoing US secretary of state, Antony Blinken, said last week the US believed Hamas had recruited as many fighters as it had lost since the start of the war.

As during previous Middle East crises, the US president might have been expected to step in at this critical juncture to ensure both sides keep their word and the ceasefire becomes a permanent peace. But Trump is not that kind of president. He worried that the war would overshadow his big day. Now his attention is moving elsewhere. He offers no plan, no fresh ideas – only wishlists, threats and prejudices.

If the leaders of Israel and Hamas do decide to go at it again in the coming weeks and months, there may be no stopping them – despite the fact that most Israelis, Palestinians and a watching world yearn for peace.

• Simon Tisdall is the Observer’s foreign affairs commentator

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