Article 51 recognizes states' rights to individual or collective self-defense. Israel has a plausible self-defense claim based on the Iranian regime's proxy attacks against it, and its explicit mission of destroying it. If we accept that premise, then by extension Israel's allies also have a right to act in its defense.
There could also be separate arguments that the Iranian plot to assassinate Trump gives the US casus belli.
Article 51 recognizes states' rights to individual or collective self-defense. Israel has a plausible self-defense claim based on the Iranian regime's proxy attacks against it, and its explicit mission of destroying it. If we accept that premise, then by extension Israel's allies also have a right to act in its defense.
There could also be separate arguments that the Iranian plot to assassinate Trump gives the US casus belli.