Many Israelis hold him and his cabinet responsible for the security failures of October 7, and he has come under heavy domestic criticism for his handling of the war on Gaza. Add to that the fact he has long been bogged down by corruption charges and criticism over plans to change the judicial system.

Several polls show he would be forced to step down if elections were held now.

Now, as Israeli forces march deeper into southern Gaza, Netanyahu could face a decision that may have huge political ramifications for his career: Whether to send Israeli troops into the 500km (310-mile) tunnel network below Gaza.

‘Each tunnel poses a significant threat’

If Israelis were to enter the tunnel network in Gaza, it would usher in a new phase in the war, significantly levelling the playing field between the opponents, according to Philip Ingram, MBE, a former British military intelligence officer.

Above ground, Israel has waged a relentless aereal bombardment and ground invasion of the 365sq km (141sq mile) enclave, using its superiority in arms.

Underground, Hamas would be able to rely on a sophisticated network of tunnels that would channel Israeli soldiers on foot into a single file.

The challenges for the Israelis would be “enormous” due to a lack of sufficient information on where the tunnels are, how far they stretch and what potential boobytraps were laid out by Hamas in preparation, Ingram said.

From a military point of view, the Israelis would want to “avoid actually having to fight in the tunnel”, he added.

Given Hamas’s expertise in setting booby traps and ambushes, “each tunnel poses a significant threat” to Israeli troops, Elijah Magnier, a military analyst who has covered the Middle East for more than 30 years, believes.

The “Palestinian resistance appears to have a strategic advantage” when it comes to tunnel warfare he said, referencing the high numbers of Israeli soldiers who die or are injured when searching for entrances to the tunnel network.

The Israel military boasts the Weasels (Samur), a specialised tunnel-warfare unit amongst its ranks, Ingram said, explaining that the specialised troops will have “all the gadgets” and trained dogs to help navigate the tunnels.

Still, no matter how much they will have practised, he says, the reality of what is down there remains largely unknown, making it very risky.

The preparations Hamas will have made and their intimate knowledge of the sprawling tunnel network would also shift the fighting from a “360-degree conflict” above ground to a “3D” one for the Israeli troops who could face an attack from any angle, he said.

Regardless, experts believe a potential conflict in the tunnels remains a probable outcome due to Netanyahu’s promise to eliminate Hamas and its underground command centres.

Magnier believes that the recent seven-day “humanitarian pause” in Gaza “allowed Hamas and Islamic Jihad to restructure their defensive strategies and prepare for the ongoing conflict”.

There were media reports weeks ago that Israel would consider trying to gain an advantage by using poison gas in the tunnels to try to eradicate Hamas fighters in them. The idea caused an international uproar.

The Wall Street Journal recently said Israel could be weighing up flooding the tunnels with seawater as an alternative to troops having to enter.

Citing US officials, the media outlet said Israeli forces had already assembled a system of five pumps just north of the Shati refugee camp in mid-November.

The pumps would draw water from the Mediterranean into the tunnels and would be able to flood the network within weeks, the article said.

‘Eradicate Hamas’

Netanyahu committed to “destroying Hamas” as one of the responses to the attack on October 7.

And he may ultimately decide to send troops into the tunnels to save his political career, despite the risk of huge casualties, Nader Hashemi, associate professor of Middle East and Islamic politics at Georgetown University, said.

Netanyahu, Hashemi added, knows that unless he can “eradicate Hamas and … claim an ultimate victory, he doesn’t have a chance to continue in Israeli politics”.

It is not just the defeat of Hamas that Netanyahu has promised but also the release of the 125 captives Israel says are still in Gaza.

Israel believes the captives are kept in the underground networks below Gaza, which means access to the tunnels will be viewed as crucial by the Israeli forces tasked with freeing them, according to Magnier.

A military operation in the tunnels could also put these captives at risk, something else that Netanyahu may be willing to risk to secure the defeat of Hamas.

Hashemi refers to the Hannibal Directive, a mysterious Israeli military policy that reportedly allows the use of maximum force in the event of a soldier being kidnapped, even if it resulted in the death of the soldier, as an indication that Israel could “prioritise its military objectives over the deaths of hostages”.

Military costs vs political benefits

Hashemi said that even as Netanyahu looks at a potential operation in the tunnels, the question on his mind will be “how many casualties is he willing to publicly suffer” to accomplish his goal.

Ingram feels the decision will be made after weighing risks against benefits and that a likely outcome will be Israel continuing to map the network from above, using ground-penetrating radar and looking to identify key command centres which they can target specifically by “blowing a hole” in the network.

He says that although there was tunnel warfare in many previous conflicts, the “underground city” Hamas has created has taken it to “a new level”. The Israeli military is facing an unprecedented task, he said, and will need to be incredibly cautious.

When Israel could attempt to enter the tunnels remains unclear.

Israel is under pressure, Magnier said, “in the face of mounting global criticism and war crimes and crimes against humanity” and while that implies that it would need to accomplish its goals faster, “setting a specific timetable for ground operations is a challenge for any military commander”.

The Israeli advance, he says, has been “remarkably slow despite being in a small but densely populated residential area”.

Israel’s indiscriminate bombing of civilian areas has provided cover and shelter, inadvertently aiding the resistance, he explains.

If Israeli troops do enter the tunnel network, it could spell a prolonged conflict, played out underground in an information vacuum.

Hemmed in, Hamas may face fuel and supply shortages while, in contrast, Israeli troops could be “crawling for weeks and weeks just to progress 100 metres”.