As Israel considers the prospect of a ground invasion of Gaza, it confronts an agonizing human and strategic dilemma: how to deal with a hostage crisis that is inextricably connected to any potential military operation.

Christopher Costa, a former U.S. Army intelligence officer and senior director for counterterrorism at the National Security Council who convened a team focused on hostage recoveries, says he’s never seen a situation quite so complicated.

In this case, the scope of the civilian hostage problem still isn’t entirely clear. Some 150 Israelis were seized by Hamas militants in Saturday’s massive surprise attack.President Joe Biden has confirmed that there are American citizens among those captured and that there are also Italian, Thai and Austrian citizens — some of whom had dual citizenship with Israel — who are reportedly among the captives.

With Israel preparing for a major offensive, it must contemplate the risks a ground campaign will pose to the lives of those hostages. After four days of sweeping airstrikes on Gaza, Hamas is already threatening to kill a hostage every time Israel bombs a civilian Palestinian home without warning. And Gaza is a small, densely packed strip of land where the hostages invariably will be put in harm’s way by an invasion.

We spoke to Costa this week about how Israel is likely thinking about this dilemma and what a resolution could look like.

After four days of sweeping airstrikes on Gaza, Hamas is already threatening to kill a hostage every time Israel bombs a civilian Palestinian home without warning.

Hatem Ali/AP Photo

The following has been edited for length and clarity.

Calder McHugh: What details are Israel’s top intelligence officials scrambling to figure out right now?

Christopher Costa: What’s likely happening right now is Israel is trying to develop intelligence to identify the locations of where hostages are being held. So at the highest levels of the Israeli government, they’re laying out their intelligence and asking: Do we have anything that’s predictable, continuous and thorough on where the hostages are being held?

There is no plan for a rescue until you can identify where the hostages are. And I will say that this problem that the Israelis are dealing with is not like the Iranians holding Americans in one location in 1979. In that case, the United States was able to put together a rescue because all the hostages were held in one place. My conjecture is that’s not what Hamas would do — they would not consolidate hostages in one location. They would put them all over Gaza in different locations, probably underground.

McHugh: Hamas is threatening to kill a hostage every time Gaza is attacked by the Israeli military without warning. How does that affect the Israeli government’s response?

Costa: I don’t think Israel has ever been in this position. This is so immense, that at the end of the day, Israel is going to have to make some tough calls. And there may be hostages that are killed, although Hamas doesn’t have a long track record of killing hostages. It’s just a tough, tough problem.

Another difficulty is that one of the forces that would do the rescue — the YAMAM [Israel’s National Counter Terror Unit] just took on significant casualties; multiple individuals have sadly been killed in the initial battles that played out in the first 24 hours. So it’s going to be a tough problem. I think the United States moving a carrier in the region provides some deterrence, but mostly that deterrence, I think, is directed at Iran, even though that hasn’t been explicit.

I should say all of this is right out of the Iranian playbook. They were the ones that started exploiting hostages in Beirut in the 1970s and 80s.

McHugh: What happens if hostages start to be publicly killed?

Costa: When you start showing videos, hypothetically, of Israelis being killed as a reprisal for an Israeli strike that didn’t meet some kind of criteria, that Hamas was unaware of the strike or they were unable to move people (regardless, they’re not going to be honest brokers), then there’s going to be more pressure on the government. In a similar way, there was pressure on the United States to act when ISIS started beheading Americans in orange jumpsuits. It’s an emotional issue and passions are going to be unleashed on all sides of this fight by Israelis as well as Palestinians. Unbridled passion.

So I don’t know how this is going to end. But I do know that it poses the ultimate strategic dilemma for Israel. I will say, there is hope that there are brokers in the region that can start to have communications with Hamas, like the Qatari government — they have a relationship, they can start talking to Hamas. Those aren’t going to be direct Israeli talks. But they certainly have a track record of de-escalating problems in the region, and they brokered with Afghanistan. So there is some diplomatic outreach that could play out, but the Israelis have to consider diplomatic, intelligence, military rescue responses, and they have to worry about the long-term and the calculus of Iran as well. All of that has to be factored into the decision-making.

“I don’t think Israel has ever been in this position. This is so immense, that at the end of the day, Israel is going to have to make some tough calls,” said Christopher Costa, a former U.S. Army intelligence officer and senior director for counterterrorism at the National Security Council.