“If Iran closes the Persian Gulf Saudi Arabia will simply build an oil terminus on the Red Sea.”
So, let’s say Iran is now in the position North Korea occupies. NK sank the Choenan and we did nothing. Why? They “might” have a nuke. (We don’t really know.)
So, Iran goes nuclear. They require a payment to use “their Persian Gulf.” It’s half the value of your cargo. Saudi Arabia builds a terminal on the Red Sea.
But Iran, which can no longer be punished or threatened has 30-70 thousand mines ready to deploy. They drop a few hundred at the narrow entrance of the Red Sea.
Do we do anything? (I was program manger on a US Navy mine sweeper project. I have a good idea of the Navy’s capability and it doesn’t come close to being able to neutralize the number, type and quantity of mines Iran can deploy.) Will we punish Iran for doing this? Oh, we’ll send nasty letters. But that will be it.
Depends on the stakes. But even if we don't get involved Saudi Arabia certainly would in that scenario, and I wouldn't discount their military capabilities in their own back yard. And don't forget Israel also has a port on the Red Sea.