Opinion: Israel ground attack on Gaza would be a long, deadly ordeal

Editor’s Note: Peter Bergen is CNN’s national security analyst, a vice president at New America, a professor of practice at Arizona State University and the host of the Audible podcast “In the Room With Peter Bergen,” also on Apple and Spotify. The opinions expressed in this commentary are his own. View more opinion at CNN.

It will be long, bloody, and complicated. That’s the way two leading experts on urban warfare described the prospect of a ground attack by Israel on Hamas’ base in the streets and tunnels of Gaza.

Colonel (Ret.) Liam Collins and US Maj. (Ret.) John Spencer co-authored the book “Understanding Urban Warfare.”

Collins is the executive director of the Madison Policy Forum, a senior fellow with New America and a US Army Special Forces officer. He served for 27 years with multiple deployments to Afghanistan and Iraq.

Spencer is chair of urban warfare studies with the Modern War Institute at the US Military Academy at West Point. He served 25 years as an infantry soldier, including two combat tours in Iraq.   

They provided a sobering assessment of Israel’s capabilities, saying they don’t think the Israeli military is prepared for the large-scale urban combat they will likely encounter in Gaza. This type of operation can take many months because an advanced military like the Israel Defense Forces (IDF) loses many of its advantages when fighting in a city.

The experts said Israel does retain some advantages, such as specially developed armored bulldozers that can be used in urban combat and the ability to fight at night, but that must be weighed against their lack of experience and training in urban combat. At the same time, Hamas has more than 200 hostages, human shields, suicide bombers, tunnels, booby traps, many civilians that remain trapped and has had years to dig in.

If the Israeli invasion goes ahead, they estimate that the IDF will destroy “80 to 90” percent of Gaza’s urban areas and the operation “will change the landscape of this area for decades.”

PETER BERGEN: What is the IDF’s record on urban warfare of this type?

JOHN SPENCER:  Not much.

The biggest gap in the IDF is not their training areas or their tanks. It’s in a body of knowledge on how to do this big of an urban operation as fast and effectively as possible. To be clear, all militaries, to include the United States, are not trained, manned or equipped for this type of urban battle.

LIAM COLLINS:  I don’t think their military is prepared to conduct large-scale urban operations.  When you go to Israel and try to find their large urban training center, like many other militaries, they have something, but it’s not what you need to train for something like Gaza.

Israel has been extremely effective at antiterrorism operations in Jerusalem and elsewhere in the country, but that doesn’t translate to large-scale military operations in an urban environment.

SPENCER:  There are a lot of unknowns that will be encountered, both on Hamas capabilities — everything from surface-to-air missiles to what don’t we know about that Hamas has in preparation for a likely retaliation by Israel.

BERGEN: Let’s talk specifically about the obstacles the Israelis face in Gaza: Hostages, human shields, suicide bombers, tunnels, cross-border tunnels, improvised explosive devices and booby traps, and many civilians. There is also no element of surprise here.

For political reasons, given international pressures, the Israelis also may want to make this operation in Gaza as short as possible. On the other hand, for military purposes, this could go on for months, right?

SPENCER:  I say it would take months to do the mission in Gaza.

BERGEN:  What advantages does an advanced military like the IDF lose in a well-populated, dense urban space?

SPENCER:  They lose the ability to use advanced technologies to strike the enemy before you get close to them, which is what all militaries want to do. That’s why urban warfare is the most difficult, because all those superior advantages that a big military has are reduced and, in some respects, eliminated.

They lose the ability to do “combined arms maneuver.” The whole concept of combined arms maneuver from World War II to today is about having mobile forces that can maneuver around the enemy and envelop them. You’re not going to do that in an urban area. No military wants to funnel its forces into a single street or multiple single streets.

COLLINS:  To provide some tactical-level examples, there are so many opportunities for the enemy to hide and move without being observed by the intelligence surveillance and reconnaissance platforms, or drones up in the sky. They can’t see the enemy because they’re moving through tunnels. The enemy can move between buildings by blowing walls from one building to another. And then, in terms of the firepower, even if you see them, you can’t always shoot because there might be another building in the way, and then all the while, you have to be concerned about civilians in that area.

SPENCER:  The other thing they lose is the effects of their weapons.  In the concrete jungle of urban warfare, most of your weapons may not even penetrate the building the enemy is in. Yes, there are many that do, but most of the standard-issue weapons don’t.

BERGEN:  Because?

COLLINS  I’ll give an example.  Back in 2002, we dropped two 500-pound bombs on a small compound in rural area of Afghanistan, and somehow this Taliban fighter lived through that and threw a grenade at us. These structures provide inherent defenses for the defender.  You look at the destruction of a building and think no one could have survived that, but people routinely do.

Hamas wants to buy as much time as possible. The longer the urban fighting lasts, the more that political pressure will build for Israel to stop the attack due to the collateral damage and civilian casualties that are an inherent part of urban war. Their goal isn’t to destroy the IDF.  They can’t.  It’s to buy time.

BERGEN:  The Israelis presumably retain some advantages?

SPENCER: D9 Bulldozers. Two-story remote-controlled bulldozers that can go forward and take the enemy’s advantage away. The advantage Hamas has is that it’s hidden in concrete buildings. Still, if you lead with an armored bulldozer that can take the first strike of anything — for instance, RPGs (Rocket Propelled Grenades) — that gives you the advantage to take away the concrete building protection that the enemy relies on. So that’s one of the low-tech solutions that the IDF built, a capability the US military doesn’t really have.

COLLINS:   The Israelis also retain night-fighting capability; doing the attacking at night is to their advantage because that does favor them more than the enemy.

BERGEN: How do you suss out what the tunnels look like if you don’t have overhead imagery?

SPENCER:  The overhead imagery won’t help you at the depth that some of these tunnels are at. You have to have specific underground mapping technologies.

BERGEN:  What about using robots, and what about using tear gas in tunnels?

SPENCER:  Tear gas is an effective way to clear a building of enemy personnel, without destroying it.  It is unlikely Israel will use it because of the political aspect of it; what does it look like when Israel is using gas?

BERGEN: You quote the Australian strategist David Kilcullen in your book: “Cities are sponges for troops.” Why?

SPENCER:  Because of that force power that you need to clear even a street. You’re not going to bomb your way to that. An urban defender of a much smaller size can soak up your entire military, but that isn’t to say that it’s not a mission that can be accomplished. It just requires a lot of force and power, including a lot of soldiers.

COLLINS:  And the other challenge with the urban environment, too is you could clear an area, but as soon as you leave that building, you can no longer assume it’s cleared because the enemy may circle back on you using tunnels or through the walls of other buildings. They may get behind you and then reoccupy a building or an area as soon as you leave it.

BERGEN:  Snipers are a tough problem. Presumably, Hamas has snipers who are going to be entrenched, and they know the terrain very well.

SPENCER: There are a lot of lessons learned from the last 20 years of urban battles, to include acoustic sensors that can tell you where a sniper is.

Also, if you’ve ever seen an IDF soldier, they have a very large bag that goes to the top of their head. It’s a special type of camouflage. The IDF wears on their heads these bags that cover their helmets to fool snipers

BERGEN:  What about robots on the Israeli side?

COLLINS:  They will, without a doubt, employ them, but they probably don’t have as many as they would like, and they’re slow.

BERGEN: Hamas provides garbage removal. It provides some social services. It was elected a government in 2006. There’s been no election since. But it functions on multiple levels. It has a terrorist component. Does that complicate things?

COLLINS: You have this hybrid organization that’s a terrorist organization and a paramilitary organization that provides government services.

So, Israel is not — despite stating that the goal is to “destroy” Hamas — they know that’s unrealistic. That’s just a political statement they have to say. Their goal is to degrade them and prevent a future attack. So, really, what they’re going after is the leadership, the terrorist wing, the fighting wing of Hamas.

So, they will call the end to the operation when they feel that they have culminated in terms of the diminishing point of returns on degrading additional capability versus the political cost of continuing that operation to degrade additional capability.

BERGEN:  What does the day after the fighting stops look like in Gaza?

COLLINS:   It’s people moving back to their houses. You’re removing rubble. You’re   trying to get services back up and running. Nongovernment organizations are coming in and trying to restore some semblance of normal life to the Palestinians.

BERGEN:  The Israelis already pulled out of Gaza back in 2005 because it was too big of a headache, and the Israelis that I’ve spoken say, “We’re not going to hold Gaza,” but, if that’s the case, then who is?

SPENCER:  Militaries have an abysmal record at building states or nations or building cities in general. Who will govern Gaza?  Who is going to provide services and security and reconstruction? That’s a massive question.

BERGEN:  Let’s go to Mosul, the second largest city in Iraq that was taken by ISIS in 2014. In your book, you write about one hundred billion dollars’ worth of damage to the city during the fight to clear ISIS out of Mosul from late 2016 into 2017.

SPENCER: ISIS had two years of defensive planning and building a defense in depth with massive obstacle belts in Mosul, and that is why it took nine months for a hundred thousand security Iraqi forces — albeit nothing like the IDF — backed by the US with the world’s best air power to discriminately, building by building, destroy most of Mosul.

That’s a telling sign of what it would look like to accomplish the current mission we think the IDF will get. It will destroy 80 to 90% of the infrastructure and buildings in Gaza’s urban areas. This will change the landscape of this area for a generation.

COLLINS:  People should know that even under the most stringent laws of war, cities are destroyed in order to accomplish this type of mission.

BERGEN:  Israel seems like a tank-based army. Walk me through what tanks in an urban environment can do and the advantages and disadvantages they have.

COLLINS:   Tanks have a huge advantage in the open desert. But many of their advantages get neutralized or lessened when you enter the urban environment. Their ability to range targets from a distance is greatly reduced and they can’t elevate their main gun to engage targets in tall buildings. So, you need a tank as part of your combined arms team in urban combat, but it’s much more vulnerable there than it is elsewhere.

SPENCER:  Of all the challenges inherent to this type of urban combat, the tank is extremely vulnerable.

But there is no other tool that is as vital as the tank when you fight in a city, because it can go down a street and take the punch of the defender. It has a firepower unique to ground forces that it can punch through concrete, and it has the mobility to move around.

The disadvantage, of course, is that it can’t see everything. It is vulnerable. It is slow. You can see it coming. So, it has to be protected with infantry.

BERGEN:  So, you’ve got to have substantial amounts of infantry protecting the tank?

SPENCER:  Right. That’s the lesson of the Ukraine war; Russia is an artillery tank-based army, so when it entered Ukraine in early 2022 they had reduced numbers of infantry and they lost an ungodly number of tanks.

COLLINS: You need the infantry to protect the tank, but you need the tank to protect the infantry.

BERGEN:  Doesn’t this have some implications for the “mass” involved when you launch a military operation in Gaza? Defending is easier than attacking?

SPENCER: We usually say this is the “combat power.” In an open terrain, you need three combat powers — some people just say troops — to one defender. In urban terrain, historically, you need fifteen or ten to one combat power because you can’t mass in urban areas.

One street can suck up an entire battalion just to try to move down that street.

BERGEN:  And a battalion would be 800 troops?

SPENCER:  Up to 900.

BERGEN:  Let’s just do some math here, what does it look like in terms of the size of the force that would need to be sent into Gaza?

SPENCER: There’s a lot of variables there, but it’s about power, not numbers. This isn’t the Battle of Berlin in 1945 where the Soviets put a battalion down every street. This is why urban battles also happen repeatedly, because nobody has a million-man army anymore. They have smaller armies, where a small opposing force can gain power in the urban environment, and you have to throw a lot of combat power — usually that’s artillery — to get them out.

BERGEN:  Let me ask you, Liam, about the hostages because you come from the US special operations community.

COLLINS:  I’m pretty confident that they don’t have the intelligence of where the hostages are located. They are most likely hiding them underground. And you absolutely need that kind of intelligence to conduct an operation, and then even if you have the intelligence, do you have the means to get there safely and get them out with a reasonable chance of success without losing the hostage and losing a significant portion of your force?

So, I think nations are probably staging their forces so that if they do get the intelligence, they can then decide if they’re going to try to rescue their citizens. But I think we’re most likely to see results through diplomatic means as was the case when Hamas released the American mother and her daughter last week.

Now, the Israeli hostages. I think those are the ones Hamas is going to hold on to the longest.

SPENCER:  To have this many hostages from this many countries intermixed with the enemy and the Israelis about to execute this operation is an unprecedented situation in my mind.   

BERGEN:  Why did you write a book on urban warfare?

COLLINS: Battles are increasingly being fought in urban areas, and militaries worldwide, including our military in the US, are underprepared or unprepared to do it. I constantly challenge people to name a significant battle in Ukraine that’s not in one of the cities.

SPENCER:  Militaries are inherently resistant to urban warfare. It is a place where they don’t want to go. So, they don’t prepare for it, and that’s why the enemy continues to resort to it.

COLLINS: But you can’t help but be pulled into urban warfare because humans fight wars, and humans live in cities.