UNCLOS has specific enforcement mechanisms behind it. I don’t know enough detail to know what they are, but yes, it’s founded on an international treaty. My point was Iran wasn’t doing it out of the goodness of their hearts, but because they got something in return: on UNCLOS specifically they get free passage for their own ships in others’ territorial waters. More broadly, they get the stability of the post-WWII international order.
The US has turned its back on that international order by attacking Iran. Therefore the incentive for Iran to participate in that order has greatly diminished.
If all international treaties are “playing nice”, then fine, they were playing nice. I prefer to see them as a mutually beneficial exchange. We’re getting dangerously close to “laws are just threats” territory though, and I think that moves us away from a conversation whose definitions are useful for dialogue.
This is a very good point, have an upvote.
The maritime treaties are the ones that I assume the most countries have signed, because they rely on such old principles, but I didn’t go check details on this one.
EDIT: Damn it, you made me go down a Law of the Sea rabbit hole, what with your “facts”.
The US hasn’t ratified UNCLOS, you’re right. But it did both sign and ratify the 1958 Convention on the Territorial Sea and the Contiguous Zone, which guarantees the right of innocent passage, which is what is at issue here. Iran also signed this treaty, though never ratified.
Further, both the US and Iran signed UNCLOS, even though neither has ratified.
Further still, Oman, who is the other half of this agreement with Iran, has both signed and ratified UNCLOS.
The US also supported the definition of innocent passage in a 1989 joint statement with the USSR.