> consideration to the harms done to non-combatants, both in the sense of "civilians" and "neutral countries".
Knocking down Starlink is perfect version of no-harms strike. Nobody dies, only person negative affected is Musk and some techno bros.
With 45% probability, assuming he isn't assassinated.
The tie with Musk would make your hypothetical very convenient for Iran as an empty threat though, so there's that.
> Nobody dies
Loads of people die from communication failures.
More importantly, this would only even be a threat if it could actually cause a kessler cascade, because there's too many Starlink satellites to target directly even if you own SpaceX.
This matters because such a cascade will also mess up everything else in close orbits regardless of nationality.
It's like hypothesising someone might use CFCs as a chemical weapon: sure, if they want to make enemies with basically everyone all at the same time.
I already told you why: They ratified a treaty saying so.
(Also: 'unprovoked'? The US isn't seeking reasons for that right now, even currently trying to lower tensions between them and Israel, and the two even had a brief period where they agreed to stuff: https://en.wikipedia.org/wiki/Iran_nuclear_deal_framework)
Furthermore, the right to self defence doesn't give countries free reign to do anything, it has to be done with consideration to the harms done to non-combatants, both in the sense of "civilians" and "neutral countries".
> And US army could not even conquer Afghanistan after 20 years. There is no way they would win.
They conquored Afghanistan in a few months; they didn't want to run the place, so they tried to build a democracy. That didn't do what they were expecting, but it doesn't matter if the threat is "does XYZ have nukes and ICBMs?"