Last week, Israel conducted airstrikes against Islamic State (IS)-affiliated forces in southern Syria, in response to their prior attack on an Israeli reconnaissance unit in the Golan. Two days later, Israeli planes reportedly flew into Lebanese airspace and fired missiles at Hizballah positions outside of Damascus, most likely targeting a weapons convoy, and perhaps also at a facility belonging to the Syrian military. Jonathan Spyer explains the two incidents:

[The IS affiliate that attacked Israel] controls an area of the [Israel-Syria] border east of the Golan Heights, [from which it] is conducting a war against the Syrian rebels to its north. It does not fight the forces of the Syrian government because they are not deployed in its immediate vicinity. . . . The volume of the Israeli response was clearly intended to reestablish deterrence against the Sunni jihadists, with the hope that it will cause them to think again before engaging with Israeli forces. . . .

Israel’s main concern, [however], is the Iran-Assad-Hizballah alliance. The reported strikes in the Damascus area, if they took place, were the latest incidents in a limited Israeli campaign against these elements intended to produce two outcomes: first, to limit the transfer of complex weapons systems to Hizballah, and second, to keep the Iran-supported militia and its allies from replacing the rebels along the borderline. . . .

[If Bashar al-Assad and his allies succeed in regaining control over the northern part of Syria], then eventually the southern front will come back onto the agenda. . . . It is Russian air power that is enabling the regime to advance in the north. If employed in the south, it can be expected to eventually produce similar results. . . . [Moscow’s] decision as to whether to allow Assad to reconquer the southwest of his country—and by so doing to allow Iran and Hizballah to reach the border with Israel—will be decisive.

Of course, even in the worst-case scenario in which they decide to allow this, the task facing Israel on the border will not fundamentally change. It will mean that instead of needing to deter hostile but relatively weak Sunni jihadist forces from contemplating action against the hated Zionists, Israel will need to deter hostile and less weak Shiite jihadists with the same intentions. . . . Israel, naturally, prefers the weaker, non-state enemy in close proximity to the stronger. The events of this week show that it is engaged in a tacit, ongoing, unstated, and limited war against both.

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.