In April 2016, Benjamin Netanyahu admitted publicly, for the first time, that Israel had routinely attacked arms shipments in Syria in order to prevent Hizballah from obtaining advanced weapons—a policy that continues to be in force. While these attacks on foreign soil in the midst of a complex civil war might at first seem to fall into a legal gray area, there is a straightforward case for their legality, as Louis René Beres writes:

Legally, there is nothing complicated about the issues surrounding Israel’s counter-terrorist raids within Syria. By willfully allowing its territory to be used as a source for weapons that Hizballah terrorists can use against Israel, and as an expanding base for anti-Israel terrorist operations in general, Bashar al-Assad has placed Syria in unambiguous violation of both the UN Charter and the wider body of international rules identified in Article 38 of the UN’s Statute of the International Court of Justice.

There is more. Because Syria, entirely at its own insistence, maintains a formal condition of belligerency with Israel (that is, a legal “state of war”), [the] charges levied by Damascus or Tehran of “Israeli aggression” make no jurisprudential sense. . . . [Furthermore], express prohibitions against pro-terrorist behavior by any state can be found in Articles 3(f) and 3(g) of the 1974 UN General Assembly Definition of Aggression. These prohibitions are part of customary international law, identified in Article 38 of the International Court of Justice statute as “the general principles of law recognized by civilized nations.” . . .

Under international law, every use of force by states must be judged twice: once with regard to the justness of the cause, and once with regard to the justness of the means. This second standard concerns core issues of humanitarian international law. . . . In defending itself against Hizballah terror, Israel’s actions have always been consistent with humanitarian international law. In stark contrast to the Shiite terrorist militias operating in Lebanon and southern Syria, and similarly unlike the Syrian-supported Islamic Jihad forces, who intentionally target noncombatants, Israel has been meticulous about exclusively striking hard military targets in raids on Syria. . . .

[Above all], the obligation of a sovereign to protect its citizens or subjects is . . . utterly beyond question. Israel need make no apologies for choosing to defend itself against Syrian-sponsored Hizballah aggression. International law is never a suicide pact.

Early Friday morning, Israel attacked military installations near the Iranian cities of Isfahan and nearby Natanz, the latter being one of the hubs of the country’s nuclear program. Jerusalem is not taking credit for the attack, and none of the details are too certain, but it seems that the attack involved multiple drones, likely launched from within Iran, as well as one or more missiles fired from Syrian or Iraqi airspace. Strikes on Syrian radar systems shortly beforehand probably helped make the attack possible, and there were reportedly strikes on Iraq as well.

Iran itself is downplaying the attack, but the S-300 air-defense batteries in Isfahan appear to have been destroyed or damaged. This is a sophisticated Russian-made system positioned to protect the Natanz nuclear installation. In other words, Israel has demonstrated that Iran’s best technology can’t protect the country’s skies from the IDF. As Yossi Kuperwasser puts it, the attack, combined with the response to the assault on April 13,

clarified to the Iranians that whereas we [Israelis] are not as vulnerable as they thought, they are more vulnerable than they thought. They have difficulty hitting us, but we have no difficulty hitting them.

Nobody knows exactly how the operation was carried out. . . . It is good that a question mark hovers over . . . what exactly Israel did. Let’s keep them wondering. It is good for deniability and good for keeping the enemy uncertain.

The fact that we chose targets that were in the vicinity of a major nuclear facility but were linked to the Iranian missile and air forces was a good message. It communicated that we can reach other targets as well but, as we don’t want escalation, we chose targets nearby that were involved in the attack against Israel. I think it sends the message that if we want to, we can send a stronger message. Israel is not seeking escalation at the moment.