On Monday, Syrian forces fired a surface-to-air missile at Israeli planes conducting routine surveillance over Lebanon. This was not a first, but the planes in question were in Lebanese, not Syrian, airspace. In response, the IDF destroyed the battery that launched the missile—also unusual for Israel, which has generally refrained from striking so deeply into Syrian territory. Yoav Limor comments on the possible implications:
There are two ways to explain Syria’s part in the incident. The first is that it was not planned. The Israel Air Force (IAF) planes’ flight path took them further east than usual, and perhaps the Syrian troops manning the battery that night were frightened and decided to fire at them. If this was the case, the Syrians have not changed their policy, and for the moment at least there is also no special reason for Israel to worry.
The second possibility is the Syrian missile launch was the early phase of a new policy that includes a response to perceived threats not only in Syrian but also over Lebanese territory. If this is indeed the case, [the incident] constitutes a drastic change, reflecting a heightened self-confidence and a wish to relieve Hizballah—which defended the Assad regime with its own flesh and blood—of the task of protecting Lebanon.
Israel is leaning toward the first option, but there is no doubt that, in light of . . . the imminent defeat of Islamic State, . . . Bashar al-Assad is feeling confident in his rule, certainly while the Russian defense umbrella remains open above him.
This is also the reason that Israel resolved to be as clear as possible when it drew its red lines. Even though the missile did not put IAF planes at risk, another missile is likely to do so in a future incident. The Israeli response was meant to send the message that as far as Israel is concerned, Lebanon is out of bounds, and there is no better justification for an Israeli strike on Syria than if the Syrians shoot at a routine flight over Lebanese airspace.