Iran has long possessed the ability to survive decapitation and respond to an existential threat by closing the strait. It’s why no US President tried it before now. Ukraine was more of a surprise than Iran, but Russia not realizing that their own neighbor wouldn’t be a pushover the second time was still a danger that they could’ve foreseen. In both cases, deterrence didn’t work because the invaders were greedy and irrationally confident.
Neither Ukraine nor Iran had a “formidable” army when they were attacked.
Russia was supposedly the second army in the world too.
Iran has long possessed the ability to survive decapitation and respond to an existential threat by closing the strait. It’s why no US President tried it before now. Ukraine was more of a surprise than Iran, but Russia not realizing that their own neighbor wouldn’t be a pushover the second time was still a danger that they could’ve foreseen. In both cases, deterrence didn’t work because the invaders were greedy and irrationally confident.