israel has made significant progress toward degrading Hamas, but one should not assume that these tactical successes will create a benign environment for a Gaza stabilization mission in the near term. Campaigns against jihadist groups elsewhere in the world suggest that the more likely outcome is a prolonged, low-level guerrilla conflict in which Hamas sustains enough instability and local control to hinder reconstruction.

Israel Has Decimated Hamas Military Forces

At the outset of the Gaza war, the Hamas army—the Izz al-Din al-Qassam Brigades, built with Iranian sponsorship—consisted of 5 brigades organized in 24 battalions. By last month, the Israel Defense Forces had “dismantled” 22 of these battalions, according to the Prime Minister’s Office. In mid-July, the IDF stated that it had killed “half” of the group’s military leadership, including 6 brigade commanders, over 20 battalion commanders, and about 150 company commanders (these figures likely indicate the killing of new commanders who replace eliminated ones). If accurate, this assessment suggests severe disruption to a whole generation of Hamas tactical leaders—a blow that no fighting force can easily sustain. In total, the IDF spokesperson stated that Israel has “eliminated” more than 17,000 Hamas members since the start of the war, while a U.S. intelligence assessment from May estimated that the group had lost 30-35% of its fighters (though without providing precise numbers). According to the CIA, Hamas military commanders have been pushing their leader, Yahya al-Sinwar, to accept a ceasefire deal, further indicating substantial military pressure on the group.

In addition to inflicting manpower losses, Israel has upped the pressure by capturing the Philadelphia Corridor, a major Hamas smuggling and supply route along Gaza’s border with Egypt. Last month, IDF officials claimed that about 80% of the more than 150 Hamas tunnels beneath the corridor were “neutralized,” another major blow if true (though see the next section for more on the wider Gaza tunnel network). The IDF has also systematically dismantled the group’s weapons manufacturing capacity, drying up its internal rearmament efforts.

One recent report disputed Israel’s claims about heavily degrading Hamas and asserted that its battalions are recovering by cobbling together fighters, either by merging battered units or recruiting new fighters. Yet such actions could just as plausibly indicate a force struggling to generate fighting power as one rebuilding its strength. Merged units would remain severely degraded and exhausted, and most new fighters would likely be untrained individuals who were either coerced by Hamas threats or enticed by the group’s control of aid distribution. At the same time, Hamas probably does retain enough fighters to serve as a basis for reconstitution if left to their own devices.

Where Hamas has attempted to reconstitute, Israel has more easily defeated its forces the second time around. For example, after its March raid on Gaza City’s al-Shifa Hospital—an important Hamas headquarters—the IDF stated that more than 200 Hamas fighters were killed and hundreds more captured over the two-week operation, compared to two IDF combat deaths. In contrast, Israel’s initial operation to clear al-Shifa in November was more arduous, involving weeks of preparatory intelligence gathering and bombardment, encirclement of the hospital compound, and sequenced raids on each section preceded by advance warnings to evacuate civilians. Most Hamas fighters fled at the time, preventing the IDF from inflicting major manpower losses. Yet dismantling tunnels, command centers, and other military infrastructure at the hospital enabled Israeli forces to operate more effectively in the surprise March raid.

Going Underground? Lessons from Other Conflict Zones

Despite its severe military degradation, Hamas has largely maintained its grip over Gaza’s population and sought to expand its shadow governance capabilities. Coupled with its surviving fighters and infrastructure, these efforts may enable the group to impede stabilization and reconstruction initiatives well into the future.

Past cases of jihadist persistence give an idea of how Gaza’s near future might look (notwithstanding significant differences in theater size, group capabilities, ideologies, etc.). In Iraq, the United States and its partners needed eight grueling years of fighting to defeat the insurgency led by al-Qaeda’s local affiliate. In tandem with the Sunni tribal “Awakening,” Iraqi and American military forces killed numerous jihadist fighters and leaders while ousting the group to the desert. Yet terrorist attacks never went down to zero, and insurgents maintained a sizable clandestine presence in some areas. After U.S. forces withdrew in 2011, Iraqi government policies steadily eroded the country’s security forces, marginalized Sunnis, and disarmed the tribes. These and other factors created a permissive environment for the jihadists to return as the Islamic State (IS) and occupy large parts of Iraq and Syria beginning in 2014.

Another U.S.-backed campaign ensued to wrest this territory back. By 2016, IS had begun reverting to an insurgent posture, and this strategy bore deadly fruit well after the group lost its last bit of territorial control in Iraq a year later. In 2018, the group claimed 1,470 attacks in Iraq, increasing to 1,669 in 2019. IS also retained the ability to conduct mass-casualty terrorist attacks, including a 2021 suicide bombing that killed 32 people in Baghdad. With crucial U.S. support, Iraqi federal forces and Kurdish Peshmerga units gradually brought attacks down to 141 in 2023.

In Syria, IS lost its last stronghold in March 2019 but still carries out significant operations today. Attacks on Syrian military convoys occur regularly, and hundreds of IS fighters tried to seize al-Sinaa Prison during a multiday battle in January 2022. In some areas, IS extorts local residents to raise funds and exerts some level of territorial control. The first half of 2024 saw double the IS attack claims in Syria and Iraq compared to the same period in 2023, even as the group’s numbers have dwindled to “approximately 2,500” fighters overall in both countries (down from tens of thousands just a few years ago).

Another telling example comes from Somalia, where the al-Qaeda affiliate al-Shabaab has continued to operate in Mogadishu. By the end of 2011, Somali and African Union forces had ousted the group from major population centers with support from the United States and other countries. Yet it still controlled much of the country’s southern and central rural areas and was even able to conduct substantial operations in the capital, from targeting high-profile figures to raising funds and recruiting. In 2017, al-Shabab conducted one of the deadliest terrorist attacks in history, killing more than 580 people with a truck bomb in Mogadishu. Other relevant examples of jihadist persistence can be found in the Sahel, Afghanistan, Egypt, and elsewhere.

Hamas will likely follow a similar path. The organization has shown an ability to carry out small-scale guerrilla attacks even with reduced numbers, hide among the civilian population, and navigate its massive tunnel network. Although many tunnels have been destroyed, Israel has underestimated the extent of this dense network before, updating its initial estimate of 250 miles of tunnels to 350-450 miles in January after military operations uncovered more branches (for comparison, New York City’s subway tunnels stretch 248 miles). Deep enough to shield fighters from heavy bombs and at some points wide enough to move vehicles through, these tunnels substantially increase both the group’s survivability and its ability to ambush Israeli forces. In May, U.S. intelligence estimated that some 65% of Hamas tunnels remained active, reflecting the slow, painstaking efforts required to destroy this subterranean infrastructure.

Meanwhile, senior Hamas official Khaled Mashal recently urged Palestinians to return to “martyrdom operations” (i.e., suicide bombing), evoking the five-year intifada that erupted in 2000 and killed more than 1,000 Israelis. The group has also continued firing rockets from Gaza, including 537 incidents in June-August according to data from the Israel Security Agency.

Policy Implications

The IDF has made significant progress against Hamas, but sustaining these gains and securing a postwar stabilization mission will require a long military campaign. As Israel, the United States, Arab partners, and other actors consider the future order in Gaza, they should assume that Hamas remnants will retain the ability to undermine the mission and strive to reassert full control over Gaza—just as jihadist efforts persist in Iraq, Syria, Somalia, and elsewhere.

In recent months, various candidates have been floated for an international stabilization effort—for example, the Arab League has called for a UN peacekeeping force, while Emirati ambassador Lana Nusseibeh has called for a “temporary international mission.” Yet none of the countries that would presumably be involved in such missions are likely to sign up while Gaza is still torn by violence. Moreover, failure to impose an enduring defeat on Hamas may allow the rise of younger fighters who are currently gaining valuable combat experience, setting the stage for more arduous battles in the future.

So far, Israel appears to be the only actor willing to do the hard fighting that removing Hamas from power necessitates. Yet Israeli leaders may not have the political will to maintain this military pressure for much longer. Officials have already indicated that the IDF may revert to smaller raids on targets of opportunity, as with the March operation at al-Shifa Hospital. They have also ruled out implementing any Israeli governance mechanisms to challenge Hamas’s political dominance in Gaza. Accordingly, other actors—whether the United States and its allies, some coalition of Arab states, the Palestinian Authority, or a combination—will need to take on some of these burdens.

Ido Levy is an associate fellow with The Washington Institute’s Military and Security Studies Program and a PhD student at American University’s School of International Service.

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