Israel says its goal is to “crush and destroy” Hamas, but what will come next remains unclear.
Even the White House fears that Israel doesn’t have an endgame plan, sources in the US say.
How and when the conflict ends will depend on a number of variables, not least what Israeli forces find when they enter Gaza.
They also have to contend with the risk of the conflict becoming a war on two or even three fronts.
Here we look at six possible scenarios for the Israel-Hamas war.
Israel may aim for a time-limited incursion in which nearly all Hamas members are killed, followed by the withdrawal of Israeli forces relatively quickly.
A victory over Hamas in military terms would mean the death or capture of all 30,000-40,000 members of the group and the destruction of its military infrastructure, such as rocket launch sites.
It would also require the elimination of the elite Nukhba commando unit and the death or capture of the group’s entire political leadership – though Hamas’ overall political leader is based in Qatar.
At the top of the kill list is Yahya Sinwar, the leader of Hamas inside Gaza, and Mohammed Deif, its military chief.
Israel’s order to Palestinians to flee south of Wadi Gaza suggests it is already trying to bisect the strip: a northern half where most of the fighting with Hamas would occur, and a southern half where Palestinian civilians are held.
Israel says it has evacuated Palestinians for their own safety. It says they will be able to return “when another announcement permitting it is made”.
If the Israeli assault succeeds militarily, Gaza would need new leadership, something that the Israelis would tightly control.
One option might be the Palestinian Authority (PA), which is led by the Fatah movement and governs the West Bank, extending its control to the Gaza Strip. This would reverse the outcome of a 2007 civil war in Gaza, in which Fatah was forced out of the territory after an election loss to Hamas.
Whether Mahmoud Abbas, the president of the PA, has any appetite for this is unclear. The deeply unpopular Palestinian Authority co-operates closely on security with Israel – so closely that it has faced accusations from Palestinians of being a de facto wing of the Israeli military occupation, a charge it denies.
“The preferred situation for Israel, and the one favoured by the US, is to see an alternative Palestinian leadership in Gaza, most likely the Palestinian Authority,” said Dr Julie Norman, a Middle East expert at University College London.
“But the PA is viewed as woefully weak in the West Bank and would likely lack legitimacy in Gaza, opening the door for a potential power vacuum.”
Israel may choose to extend its decades-long military occupation of the West Bank into Gaza, a massive task that will require huge numbers of troops to remain in the Strip for the foreseeable future.
Such an occupation would last for years or potentially decades, rather than months – the latter being the rough timescale Israel has put on a future ground invasion.
It could involve breaking up the Gaza Strip into non-contiguous patches of land; the apparent attempt to bisect Gaza into militants in the north and civilians in the south suggests this is already under way.
Israel President Isaac Herzog appears to have already ruled this scenario out. “We have no desire to occupy or reoccupy Gaza. We have no desire to rule over the lives of more than two million Palestinians,” he said in an interview with CNN over the weekend.
US President Joe Biden has also urged Israel against that course of action, calling it a “big mistake”. Abbas is also said to be firmly opposed to a long-term occupation of the Gaza Strip. While the PA has extremely limited influence over Israel, its status as the potential new government in Gaza may give it some leverage on that front.
As of Monday, around half of Gaza’s two million-strong population has been ordered by Israel to flee from the north to the south.
This internally displaces them to an area that shares a border checkpoint with Egypt – the Rafah crossing – which they would be able to flee across if it is opened by Egyptian authorities.
But some reports suggest many Palestinians could refuse to flee the Strip. They fear a second Nakba – “catastrophe” in Arabic – echoing May 14, 1948, the day when Israel declared independence and 750,000 Palestinians subsequently fled or were expelled from their homes.
A key concern is that even if Palestinians flee temporarily to Egypt’s neighbouring Sinai region, they may never be allowed to return.
In any case, Egypt has so far been extremely reluctant to open Rafah, a move that would involve hosting hundreds of thousands of Palestinian refugees.
Egypt President Abdel Fattah El-Sisi is clearly hoping to avoid that scenario for domestic political reasons, not least of all the administrative and financial costs.
He may be particularly concerned about members of Hamas entering Egypt under the cover of a civilian exodus, and potentially beginning to wield influence in his country in the future. Though the Sisi government mediates between Israel and Hamas, it is no fan of the group’s Islamist ideology.
Hugh Lovatt, a senior Middle East analyst at the European Council on Foreign Relations, said mass displacement “could, of course, play into the hands of hard-right Israeli voices who have long called for Israel to re-establish settlements in Gaza”.
“As violence escalates in Gaza, they may also see a chance to drive out a significant part of Gaza’s population into Egypt and prevent their future return – in what many Palestinians now fear could be another Nakba,” he said.
This would be ethnic cleansing, which according to the United Nations is not just classified as a crime against humanity but a potential violation of the Genocide Convention.
The settler movement, which still wields a great deal of influence over Israeli leaders, remains deeply embittered about the 2005 disengagement from Gaza, when 21 settlements were evacuated.
Any battle with Hamas would be long, hard and costly for Israel. The Islamist group has at least 30,000 well-armed and trained fighters who will have the advantage of defending territory they know extremely well.
The “colossal” security failure that allowed hundreds of Hamas terrorists to break into southern Israel has raised serious questions about the competence of Israeli intelligence and army chiefs.
Survivors of those massacres complained of long delays in Israeli troops reaching their locations as they pushed Hamas back across the Gaza border.
Colonel Roy Levy, one of the most revered unit commanders in the Israel Defence Forces, was slain in battle with Hamas terrorists, a sign the group has refined its training and tactics.
In other words, Israel has never faced a military test like this before.
If an offensive falters and huge numbers of Israeli troops start returning to families in body bags, Israeli Prime Minister Benjamin Netanyahu could be forced to cave to pressure to limit the scope of a ground offensive, or call it off, then fully commit to hostage negotiations.
There are currently at least 200 Israeli hostages inside Gaza and secretive talks are already under way, with a focus on saving some women and children. Qatar, Turkey and Egypt are mediating those talks, but so far, little progress seems to have been made.
The priority appears to be exchanging women and children in Gaza for Palestinian counterparts in Israeli security prisons.
But a more ambitious deal would involve swapping all 200 Israelis held in Gaza for around 5000 Palestinian security prisoners being held in Israel. Some Hamas officials claim this was the ultimate goal of the October 7 massacre.
In the case of the famous Shalit prisoner exchange of 2011, a single Israeli soldier, Gilad Shalit, was swapped for around a thousand prisoners.
Gershon Baskin, a top hostage negotiator involved in the Shalit exchange, has suggested that there may be an alternative to a ground invasion.
While stressing that Hamas is “unfit to exist and unfit to govern and rule” in a Times of Israel column, he said Israel’s goal of completely destroying Hamas was just a “slogan”.
He went on to suggest an idea of his own: that Hamas frees hostages, transfers rule of the Gaza Strip to the United Nations and in return is given safe passage from Gaza to a sympathetic Arab country. He acknowledged the idea was extremely unlikely to work, however.
Iran and its lead proxy group Hezbollah have threatened to join the war if a ground invasion occurs. Only the regime’s leaders in Tehran and Hassan Nasrallah, the leader of Hezbollah, will know for sure if this is a bluff.
Hezbollah also has a presence in Syria, while some pro-Iran proxies in Iraq have also made threats to attack Israel this year. The rebel Houthi faction in Yemen, which is believed to possess medium-range missiles that could reach Israel, is also considered to be a proxy of Iran.
That creates a risk of what the Israelis call “multi-front” warfare, an event they have been warning about for years: incoming missiles from Iraq, Syria, Lebanon and perhaps even Yemen at the same time.
This may well explain the apparent delay in Israel launching a ground invasion. War with Iran and its proxies would be even more costly than war on Hamas, especially as Hezbollah in particular possesses much more powerful weaponry.
“The prospect of regional escalation is clearly a concern,” said Norman. “American diplomacy has been in full force with Arab partners this week to try to contain the conflict.”
“But the real wild card will be Iran and [whether] it will move to fully activate Hezbollah to open a northern front against Israel. Despite cross-border escalation, we’re not at that point yet, and the US, Israel, and regional partners will be seeking to deter that move.”
This is the most extreme scenario, and one that no sane leader would want to bring upon themselves.
If Hezbollah and Iran join the war, the United States will face overwhelming pressure to launch direct strikes on both entities. Washington has already put F-15 bomber jets in Jordan and sent two aircraft carriers to the region. Britain, which has sent Royal Navy vessels to the Mediterranean, would be in the same situation.
This in turn creates the risk of a direct US-Iran war. Iran’s nuclear programme would most likely be destroyed by joint Israeli and US attacks, breaking its most potent tool for putting pressure on the West. Iran’s leaders will have taken this into account when discussing the prospect of joining the war.
Russia, a key ally of Iran, may choose to get involved as well. In recent months, Iran has become a major supplier of drones and missiles to Moscow as part of a growing military alliance.
At that point, all bets would be off and the risk of a global conflict could not be ruled out, though this remains the most nightmarish and remote scenario.
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