Of course, deterrence is not the only strand in Israel’s strategy to counter its enemies. Full-spectrum prevention of terrorist attacks includes detection (deep penetration to identify threats), defense (such as the Iron Dome missile-defense system and secure walls or fences on all borders) and decisive defeat (when, despite best efforts, attackers succeed). While many states, including the United States, invest heavily in similar efforts, Israel is unique in its placing deterrence at the core of its counterterrorism strategy.

The IDF accepts the fact that this strategy sometimes fails. When it does, Israeli citizens die. But Israel’s national-security community still considers deterrence better than any feasible alternative for meeting threats posed by its substate adversaries. And after each conflict, the IDF has redoubled efforts to establish a new level of deterrence.

Israeli security professionals readily admit that they cannot successfully deter all terrorists. In particular, lone wolves who conduct terrorist attacks with little preparation remain a persistent, unsolved problem. Only days before the Orlando attack, Israel experienced its own lone-wolf attack in which two Palestinian cousins using homemade guns killed four civilians at an upscale shopping mall in Tel Aviv. Israel’s security establishment has tried to deter future lone-wolf terrorists by demolishing the attackers’ homes and taking other punitive actions against their families and communities. Nonetheless, Eizenkot noted recently, “I have to stress the fact that there is virtually no way to stop every terrorist planning a stabbing attack.”

 

TO MEET the threat of ISIS today, the IDF is following essentially the same script. Officials have been reticent about discussing details of the strategy in public, but its outlines are clear in the IDF doctrine, and senior Israeli military officials confirmed this reading of the strategy in recent off-the-record meetings.

In stark contrast with the United States, Israel sees ISIS as just one more armed group fighting in Syria alongside Al Qaeda and other terrorist affiliates. For each of these adversaries, as well as for state actors including Iran and Assad, Israel has conveyed three “red lines”: no attacks on Israel; no transfer of advanced conventional weapons (namely precision-guided missiles and rockets) to terrorist groups that threaten Israel; and no transfer of chemical weapons to terrorist groups. The “dozens” of Israeli airstrikes in Syria that Prime Minister Netanyahu recently acknowledged are calculated components of a strategy that reminds all adversaries of the cost of even minor violations of its rules. It was no accident that Israel reportedly killed a prominent Iranian general last year on the Syrian Golan Heights as he surveilled the Israeli border, planning strikes on Israel. Nor was it coincidental that Israel reportedly killed Hezbollah operations officer Samir Kuntar in December—after Israel discovered him plotting attacks on Israelis.

On its immediate border, Israel faces two ISIS affiliates: Wilayat Sinai (Sinai Province) on the Egyptian peninsula, and the Yarmouk Martyrs Brigade on the Syrian side of the Golan Heights. While both are small, their proximity and firepower concern Israeli military leaders. Despite their capability to attack at a moment’s notice, both have exercised restraint. Since declaring allegiance to ISIS in November 2014, Wilayat Sinai has focused primarily on fighting the Egyptian security forces, not Israel. Its most noteworthy success was the downing of a Russian airliner in the Sinai in October 2015, which did not kill or injure any Israelis. On the Golan, the Yarmouk Brigade controls a ten-square-kilometer area where some forty thousand civilians live. Despite the fact that the group stands, as one Israeli newspaper put it, “several hundred meters away from reaching Israeli school buses,” it has not conducted a single attack against Israel.

Israeli strategists emphasize relevant similarities between ISIS, Hamas and Hezbollah: each controls territory, attempts to govern a population and, therefore, has something to lose. Even though ISIS propaganda recently declared in flawless Hebrew that “soon there will not be one Jew left in Jerusalem,” the groups have largely refrained from attacking Israel. The reason, according to Eizenkot’s predecessor, Benny Gantz, is that “they would lose,” and in doing so risk their population and assets. ISIS leaders appear to have heard this message. As a German journalist who was embedded with ISIS in 2014 explained, “The only country ISIS fears is Israel. They told me they know the Israeli army is too strong for them.”

Could the United States deter ISIS? At least one of President Obama’s speechwriters thought so. At the National Counterterrorism Center in December, the president directed his remarks to ISIS leaders: “We’re sending a message: If you target Americans, you will have no safe haven.” If I were teaching Strategy 101 next semester, this statement would lead my weekly quiz. The assignment would simply reproduce the quote and say: “Assess.” Any student unable to explain why the president’s threat fails to satisfy the elementary requirements for successful deterrence would not receive a passing grade.

Obama made this threat just days after ISIS’s attack in Paris, which killed 130 people. His objective was to dissuade ISIS leaders from ordering a similar attack on the United States. If you attack us, the president warned, America will respond by attacking you. Students of deterrence would remind Obama that he is already conducting a campaign of air strikes and special-operations raids that he says aims to kill ISIS’s leaders and destroy the organization—before they attack the homeland. Moreover, he has argued at length why, he believes, the current campaign includes everything the United States can productively do to destroy ISIS. Thus, his attempt to deter ISIS by threatening more rings hollow.

A few months from now, a newly elected president will be thinking about how he—or she—will deal with ISIS. One can be sure that the president-elect will ask her/his national-security team to conduct a fundamental reassessment of the war against ISIS, Al Qaeda and the dozen related strains of Islamic jihadi terrorism. A serious review would begin with recognition of a brute fact: a decade and a half beyond the 9/11 attacks and President Bush’s declaration of a “War on Terrorism,” the United States undoubtedly faces more terrorists determined to do harm than when this effort began.

In anticipation of that review, the analytic community should be studying Israel’s playbook now. The United States is not Israel. Deterrence is not the only strand in Israel’s defense strategy. Not every strategy that works for Israel is appropriate for America. At this point in the fight against ISIS, it is hard to imagine a path back to a posture of containment and deterrence. But as America confronts the next ISIS, or indeed, the next dozen strains or mutations of this cancer, the United States is unlikely to have the resources and will to send even American drones and special-operations forces to every ungoverned space or valley ruled by a hostile terrorist group. Standing as they do on the front line confronting deadly threats 24/7, Israel offers what Eizenkot has called a “laboratory” of security. It is not too late to begin a debate about how lessons learned by Israel’s security community can enrich America’s conceptual arsenal for countering terrorism in what promises to be a very long war.

Graham T. Allison is director of the Harvard Kennedy School’s Belfer Center for Science and International Affairs and a former assistant secretary of defense for policy and plans. He is the author of the forthcoming book, Destined for War: America, China, and Thucydides’s Trap.

Image: “Soldiers from the Bedouins Reconnaissance Battalion trained in southern Israel.” IDF photo, CC BY-NC 2.0.