> The actual blunder was exposing that weakness to the world.
The world already knew.
The real strength of the prior admins was in simply not needing the military force. The 2015 Iran nuclear deal is a relevant example here. It didn't cost the US anything.
The Khomeini regime was always allowed to murder its own citizens, within its borders, with impunity. That's one of the priviledges of a sovereign state.
Yes they did, to the best of anyone's knowledge they did adhere to the nuclear deal until it was cancelled by Trump. Do you have sources that contradict this?