“This rogue and terrorist regime and its accomplices bear responsibility. The Islamic Republic of Iran will not hesitate to exercise its inherent right to self-defense, as enshrined in Article 51 of the United Nations Charter to respond decisively and promptly, “ the letter was reported to have said.
(The only letter I see on Iran's foreign ministry site from that same date to the Security Council does not use this same language and does not invoke Article 51.)
The Western world doesn't even blink at Iran's hypocrisy of justifying attacking Israel as self-defense. That same foreign ministry also praised the October 7 attacks as "the oppressed Palestinian people’s inalienable right to defend themselves."
In both cases, the point is that no one should deny the rights to attack Israel and Jews. No matter what the circumstances, it is always "self defense."
In reality, Iran is really concerned with honor, not defense. Iran's honor was devastated by the clear breach of their intelligence services that led to Ismail Haniyeh's assassination. Iranian "investigators" are strenuously denying the obvious - and the only reason why is to maintain the facade of "honor" and avoid shame.
Israel's target was Hamas, not Iran. Iran wasn't attacked - not a single Iranian was hurt. But the attack shamed Iran.
Any Iranian attack on Israel is meant to restore honor, not deterrence.
Honor is not an inherent right under international law. Yet because of the ingrained honor/shame mindset of much of the Muslim world, it is being tacitly accepted even by the West as a legal reason for reprisal.
Bizarre, twisted honor/shame ideas have infected international law.
No one in the West is publicly saying that Iran has no legal justification for an attack that even Iran calls "vengeance." On the contrary, the legality of this manifestly illegal action is accepted, and the only negotiations happening behind closed doors is to calibrate the intensity and scope of the revenge attack to maintain "honor", not to stop it altogether.
Al Jarida has an unconfirmed report that the US has told Iran that any attack must meet four conditions: (1) That it not be directed at civilians; (2) that it not target civilian infrastructure; (3) that the targets be military; (4) that the response be a one-off, not a succession of attacks; (5) that the regional response not be aimed at destroying much in Israel, but be symbolic. If true - and the April attack by Iran indicates it might be - that means that the West now accepts "honor" as a valid justification for an attack as a part of "self defense" as long as the affronted nation is Muslim. Iran is being told, whether explicitly or implicitly, that they can use military means to restore their own perverted sense of honor.
"Honor" is symbolic. It is wholly psychological Hundreds of rockets and drones and bombs are not symbolic. They are real. Attacking in such a way to avenge an assassination is not only a violation of the UN Charter but also a violation of the principle of proportionality.
Modern international law never considers a nation's honor as having any legal weight. The West, by sanctioning a revenge Iranian attack on Israel, is now changing international law to include that as a factor when honor/shame cultures are insulted. The lack of international condemnation of Iran's planned attack is an extraordinarily dangerous development that will hurt the West for decades to come.
Assuming that Iran did indeed send the letter quoted invoking Article 51, the UN Security Council must reject the letter and the planned attack as justified self-defense. Otherwise, it is infecting international law with the theory that insults are aggression.