On the other side a bombing campaign of that sort would be devastating for Iran and a potentially fatal to the regime. Plus the added benefit for the US is that reduces some of China's oil supply for a little bit.
Discussion
You don't fight the regime with bombs. You fight it by offering better candies to the people than the others do. Otherwise we'll get Afghanistan 3.0, Vietnam 2.0, Iraq x.0 etc.
Regarding China, Putin will be happy to sell more oil to Chinese. I don't doubt Trumptard will support that ofc.
You fight regimes with everything that's available- bribes, bombs, books etc.
Vietnam, Iraq and Afghanistan are very different to Iran. For one Vietnam was all about sending a message to its allies that the US is willing to fight communism. Afghanistan is a fractured tribal society that is missing a "king" that was traditionally the center of their society. Iraq was destroyed mostly by the combined actions of Sadaam and the current regime in Iran more than anything else.
Putin and the Russia government don't think China will be a reliable customer for its oil compared to Europe. It is unlikely that China will even pay full price for the oil.
Dunno, I'm not buying it. Why would the US suddenly attack Iran because of the nuclear weapon development? That has been in the works for decades https://en.m.wikipedia.org/wiki/Joint_Comprehensive_Plan_of_Action#Background
The US is very anxious about nuclear proliferation. Plus the regime in Iran has supported gangs/militias/terrorists that have attacked Americans for 45+ years.
The regime has also shown in its actions. and devotion to its political ideology ,that it cannot be trusted by its own people let alone its neighbours.
To allow them to have nuclear weapons is a dangerous gamble.