Ten years ago, following the ceasefire that ended Israel’s second Lebanon war, the Security Council issued Resolution 1701, which increased the size and capabilities of the UN International Force in Lebanon (UNIFIL)—first established in 1978 during that country’s civil war—and gave it a new mandate to ensure quiet on the Israel-Lebanon border. UNIFIL, writes Assaf Orion, has in fact succeeded at preventing the sort of minor incident between the two countries’ armies that could spark a war. However, it has done little to keep Hizballah and other terrorist groups from attacking Israel:

Since the end of the war, more than twenty incidents of rocket fire from Lebanon into Israel have been recorded, most apparently by organizations other than Hizballah. . . . . In recent years, [though], several Hizballah attacks from Lebanese soil were aimed at the IDF, including explosive devices in the Mount Dov sector and anti-tank guided missiles, which in January 2015 killed two IDF soldiers. (In that incident, a Spanish UNIFIL member was killed by IDF return fire.) While UNIFIL participated in the efforts to contain these incidents and prevent escalation, it failed to prevent them from occurring in the first place and also failed to prevent the basic conditions that made them possible, even when specifically warned in advance. . . .

Since the end of the war, not only has nothing been done [to create] a situation in which UNIFIL’s area of responsibility . . . is “free of any armed personnel, assets, or weapons, other than those of the government of Lebanon and of UNIFIL” [to quote the language of Resolution 1701], but Hizballah has beefed up, broadened, deepened, and increased its military deployment in southern Lebanon and elsewhere in the country.

The roots of the failure lie in the flimsy foundations of Resolution 1701, [which] called on the government of Lebanon, . . . to exercise its sovereignty on every part of its soil and, using its army, demilitarize southern Lebanon. and dismantle armed militias, including Hizballah. UNIFIL was charged with helping the government of Lebanon achieve this [goal]. In practice, Lebanon is a weak state whose government, to the extent that it functioned at all during this period, was being held hostage by Hizballah, which is part of that same government. The Lebanese army too is Hizballah’s hostage and sometime partner: Hizballah is militarily stronger, and politically paralyzes the state’s military. Thus . . . Resolution 1701 was emptied of any real content even when it was formulated, and dynamics on the ground continued to deny it substance.

On Tuesday, a Hizballah drone attack injured three people in northern Israel. The next day, another attack, targeting an IDF base, injured eighteen people, six of them seriously, in Arab al-Amshe, also in the north. This second attack involved the simultaneous use of drones carrying explosives and guided antitank missiles. In both cases, the defensive systems that performed so successfully last weekend failed to stop the drones and missiles. Ron Ben-Yishai has a straightforward explanation as to why: the Lebanon-backed terrorist group is getting better at evading Israel defenses. He explains the three basis systems used to pilot these unmanned aircraft, and their practical effects:

These systems allow drones to act similarly to fighter jets, using “dead zones”—areas not visible to radar or other optical detection—to approach targets. They fly low initially, then ascend just before crashing and detonating on the target. The terrain of southern Lebanon is particularly conducive to such attacks.

But this requires skills that the terror group has honed over months of fighting against Israel. The latest attacks involved a large drone capable of carrying over 50 kg (110 lbs.) of explosives. The terrorists have likely analyzed Israel’s alert and interception systems, recognizing that shooting down their drones requires early detection to allow sufficient time for launching interceptors.

The IDF tries to detect any incoming drones on its radar, as it had done prior to the war. Despite Hizballah’s learning curve, the IDF’s technological edge offers an advantage. However, the military must recognize that any measure it takes is quickly observed and analyzed, and even the most effective defenses can be incomplete. The terrain near the Lebanon-Israel border continues to pose a challenge, necessitating technological solutions and significant financial investment.