Israel’s expected ground offensive in Gaza will be potentially catastrophic for civilian life in Gaza, while also posing steep risks for Israeli forces and raising the danger of widening a war with Iran-backed proxy groups. 

For the first time in years, Israeli forces will have to penetrate deep into Gaza, a coastal enclave where thousands of Hamas militants operate out of an underground network of tunnels, while also hiding among civilians. 

Israel’s stated goal of eliminating the group will require a long, bloody fight against guerilla combatants known to use human shields in the densely packed Gaza Strip. 

“It’s going to be very, very messy,” said Raphael Cohen, a senior political scientist at Rand Corporation with expertise on the Middle East and defense strategy. 

“Rooting all that out is not particularly easy. And in order to do that, that’s a fairly significant military operation and it will take a lot of time — potentially a lot of casualties.”

Further complicating the mission is that Israeli forces need to rescue some 150 hostages, including some Americans and other foreign nationals. 

And a large-scale attack in Gaza may open a new front in the war, with the Lebanese militia Hezbollah reportedly warning it will respond if Israeli forces invade the coastal enclave.

Israeli officials are determined to respond decisively after Hamas killed more than 1,300 people in a surprise attack last Saturday. 

A ground invasion now appears to be imminent after Israel on Friday ordered the evacuation of more than one million people in Gaza. However, many people have nowhere to go, with Egypt loath to open its border to the south. Hamas has also urged residents not to flee. Israel has blockaded the territory for years and this week cut off its fuel and electricity in a siege that has spurred warnings of a humanitarian crisis. 

After Saturday’s attack, Israeli Prime Minister Benjamin Netanyahu promptly declared war and vowed to eradicate the designated terrorist group.

Israeli forces have spent days mopping up the remaining militants and launching mass air strikes on Gaza that killed more than 1,500 Palestinians. They have also conducted limited raids into Gaza.

But if Netanyahu wants to keep his promise to purge Hamas, he will have to send troops deep into Gaza to deliver a final blow.

Analysts say the delay so far of a ground invasion is likely part of Israel’s strategy to pressure Palestinian militants with rocket strikes and to prepare for all possible contingencies, while integrating some 300,000 reservists into combat duty.

But the main reason may be to maximize intelligence gathering on the hostages to know where to strike.

Phil Andrew, a principal at the global conflict and crisis consulting firm Pax Group, said it was important to be “listening and collecting as much information as you can” and ensuring everything is in place for a rescue mission.

“It was very wise of the Israelis to shore up all their plans, their strategy, their supply, their tactics,” said Andrew. “They really have the ability to kind of determine the operational tempo at this point.”

The trickiest part of the mission will be to locate and safely extract the hostages, who are likely hidden in various locations throughout Gaza and subject to the whims of various Hamas factions and individual leaders, rather than a strict military command structure.

Andrew, who served for more than 21 years with the FBI working on hostage cases, warned that Israel was conducting a risky operation by telegraphing an intention to destroy Hamas while also trying to keep the hostages alive. That could ruin any communications channels needed for negotiations, he said, and Hamas has previously warned it will kill hostages if pressed.

Israeli operations into the Gaza Strip will also pose enormous risks for both its soldiers and Palestinian civilians caught in the crossfire.

Israeli officials have sent mixed messages on the potential for civilian casualties. Israeli President Isaac Herzog said this week an “entire nation” was responsible for the attacks on his country, though he later denied that he was justifying attacks on Gaza civilians.

Israeli Defense Minister Yoav Gallant said at a Friday press conference that soldiers will “not shoot civilians on purpose” as they attempt to “destroy Hamas” and “take these phenomena out of Gaza and out of the Earth.”

“Therefore we are asking all the civilians in Gaza City to go south of Gaza.  And the reason is that because we don’t want to harm them,” he said. “The camouflage of the terrorists is the civil population. Therefore we need to separate them. So those who want to save their life, please go south.”

Knox Thames, an international human rights advocate, said Israel “must avoid civilian casualties.”

“But Hamas often embeds its fire platforms and organizational nodes within civilian areas, using them as a shield, and when civilians die, using them as a propaganda message,” Thames said in an emailed statement.

The last decade has seen intermittent clashes between Israel and Palestinian militant groups, but nothing on the scale that Israel is promising against Hamas. 

In 2014, the last time Israel fought a major war inside Gaza, 66 Israeli soldiers died, along with more than 2,000 Palestinians, most of them civilians, according to human rights groups. The conflict was a roughly 50-day clash.

Hamas may have anticipated an Israeli ground offensive in retaliation for its barbaric attack last weekend. Since the military and political authority took over Gaza in 2007, it has built up an array of shadowy defenses across the territory, many of them underground networks.

Bilal Saab, director of the defense and security program at the Middle East Institute (MEI), said Israel has the capability to “massively degrade” Hamas’ military capabilities, but it was a question of how many casualties of Israeli soldiers and civilians Jerusalem is willing to sacrifice.

Still, Saab said the stated goal of completely eradicating Hamas will be near impossible because Hamas has political support, making it even tougher to wipe out than a traditional terrorist group like ISIS.

“I understand the political logic behind it,” he said. “You want a message to your population that you are going to extract some heavy punishment on your opponent, but there’s no way they’re going to be able to defeat a deeply rooted organization.”

And if Hezbollah is pulled into the war, that may prove even more problematic for Israel’s military than any trouble inside Gaza itself.

If Israel were forced to fight against two militant groups backed by Iran, it would be stretched much thinner and less able to concentrate on its main objective, eradicating Hamas.

Hezbollah is far better equipped and advanced than Hamas. The Lebanese militant group, an archenemy of Israel along with its creator Iran, has already begun firing rockets and artillery in nonstop tit-for-tat exchanges with Israel.

Saab said the risk of a front opening with Hezbollah was very real, but added Israel does not have much of a choice.

“If you are communicating to Hezbollah that you’re so worried about opening a second front that we’re not going to go after Hamas, that’s going to set a precedent for the future,” he explained. “They have to show that they are able to handle multiple fronts.”