In September, a Syrian chemical-weapons plant was destroyed, most likely by Israeli airplanes, not far from a high-tech Russian anti-aircraft installation. Yet Russian troops did not respond to—or attempt to prevent—this attack on their Syrian ally. Nor has Moscow acted to protect its coalition partners from numerous other Israeli airstrikes over the past few years. Likewise, Russia did not retaliate when the U.S. launched cruise missiles at a Syrian air-force base in April. Guy Plopsky concludes that, despite repeated threats, the Kremlin wishes to avoid conflict with either America or Israel:

Moscow’s warnings to Israel are . . . directed more toward the Syrian and Russian public than they are toward Jerusalem. Offering no threatening response to Israeli airstrikes would make the Kremlin appear weak, prompting pro-Assad factions to question Moscow’s commitment to the regime and weakening Russia’s influence.

At the same time, Russia has been rebuilding Syria’s air defenses in the hope that they would deter both Israel and the coalition from further strikes. Russia’s defense ministry has mentioned Syrian air defenses in warnings directed at coalition forces and has pledged to “increase [their] effectiveness.” . . .

As for Russia’s own air defenses, Moscow has not utilized them to defend Assad’s forces and is unlikely to do so for fear of an armed confrontation with the U.S. and its partners. Indeed, while Syrian fighters are known to have flown escort missions for Russian strike aircraft, the reverse has not occurred. Furthermore, like Israel, the U.S. maintains a de-confliction line with Russia and has developed agreements to avoid clashes. . . .

Contrary to Kremlin rhetoric, targeting stealth aircraft and cruise missiles remains a major challenge for Russian air defenses. Furthermore, due to the radar horizon limit, even non-stealth aircraft can significantly reduce detection by flying at very low altitudes. Also, sophisticated electronic-warfare systems can degrade the performance of enemy radar. Hence, at long ranges, [even the best Russian surface-to-air missiles] can realistically be expected to intercept only cumbersome targets successfully. . . .

This does not mean Russia’s air defenses in Syria should be neglected. On the contrary: Jerusalem and Washington must keep a close watch, particularly as the post-Islamic State stage of the Syrian conflict sets in.

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.