Go read some history about what industrial quantity of ordinance was required to somewhat destroy European cities in the 40s.
America does not have a bomber fleet capable of doing that in Iran, no matter the will.
Strategic Bombing in WW2 is an unfathomable scale.
The US, just the US not Britain (who had similar numbers on their own), dropped 1.4 million tons of ordinance on German occupied Europe. That's the equivalent of 5.6 million MK82 based JDAM bombs. The immense weight of explosives managed to degrade German cities by about one half. It took thousands of bombers to do so, including 10,000 bombers being destroyed.
If every single one of the 72 B52 bombers we still have were loaded to the gills with 140 MK82 JDAMs to fly over Tehran, we would lose many irreplaceable airframes, and would only manage to drop 2500 tons of bombs.
Dresden, which only killed 25k people and reduced industrial output by like 15% temporarily was 3900 tons of ordinance on just that one day.
And Dresden was a lightly hit target in the war. Berlin was hit with nearly a pound of bomb per human being living in it. Essen was hit with six times that
TL;DR: The people who believe this have no sense of scale.
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