Israel’s suspected bombing of what Iran describes as its diplomatic premises in Damascus, killing Mohammad Reza Zahedi—the top Islamic Revolutionary Guard Corps (IRGC) commander in the Levant—is a major escalation with reverberations on multiple dimensions.

Changing the rules of the game

In legal and operational terms, the bombing raises major questions about the state of international norms protecting diplomatic personnel and premises. Iran has described the targeted building, located next to the embassy, as a consulate that also housed the ambassador’s residence. Israeli sources have indicated that the site was bombed as members of the IRGC’s expeditionary Quds Force were meeting with Palestinian Islamic Jihad (PIJ). If the building is recognized as a diplomatic site, such a gathering would be protected under international conventions.

Equally importantly, Israel has in past months signaled that...