The issues the US faces are political and humanitarian (and economic) rather than military. I don't see any compelling evidence that the US couldn't open the straits if it really wanted to, it's just that the cost in lives and hardware would be unlike anything the US has seen since Vietnam, maybe even the second world war. And of course, once you open the strait, you have to keep it open. The whole thing is a lose-lose situation for everyone involved.
It should probably also be pointed out that doing nothing has a cost too, and it's probable that the bill for doing nothing over a long period of time has come due. I, like most people, never bought the WMD claims leading up to Iraq. I'm not sure what to think here. I certainly don't buy that Iran wasn't working towards getting the bomb after how well it worked out for North Korea. I can't claim to know the calculus involved in determining whether or not it's worth going to war with Iran to stop them from getting the bomb.
> I don't see any compelling evidence that the US couldn't open the straits if it really wanted to, it's just that the cost in lives and hardware would be unlike anything the US has seen since Vietnam, maybe even the second world war
The US invaded Iraq and toppled its government; Iraqi militias are still firing drones and missiles at US bases. Tankers and oil infra are much softer targets… all it takes is hitting one or two tankers and folks will stop shipping.
> I don't see any compelling evidence that the US couldn't open the straits if it really wanted to, it's just that the cost in lives and hardware would be unlike anything the US has seen since Vietnam, maybe even the second world war.
The second half of that sentence is literally explaining why the "impossible" you reject in the first part.
The US wasn't doing nothing about Iran though. The JCPOA was a thing, before trump tore it up. This approach is about the dumbest way Iran could be handled, which makes sense given who is giving the orders.
Given you compare the cost of a US operation to open the straits to the Vietnam War, it seems prudent to mention that the outcome of the Vietnam war, according to Wikipedia, was a North Vietnam victory.