Bombing 3 Gorges --> nuclear retaliation, simple as that.

It would depend on the/political situation...it is ENTIRELY possible the PRC would retaliate with nuclear weapons for a Three Gorges strike...such a strike would cripple the PRC, they might well respond with a high altitude attack designed to EMP the West Coast, to devastate the US economy.  Depending on the overall situation the US might or might NOT respond with a counter-city strike on the PRC.

Thank you for that well-reasoned response...sadly we don't have pre-programmed, we have PRE-PLANNED responses...there is a large difference.  Should the NCA authorize there are a number of options available to the United States, but in no case is anything pre-determined.  So yes, it is ENTIRELY within the realm of possibility that after the West Coast goes dark, the US would decide to not further attack the PRC.

 

Whether we would do so or not would depend on something you assume, but is not required, that we be in a "Central War" with the PRC.

 

Nice reference to Kahn's rung's though....no one really believed them even when they were written.

 

Your humility factor needs a rather large adjustment.  On this issue, as opposed to technical/engineering issues your opinion is merely that, one human's opinion.  It isn't budgeting or engineering or technical spec's of radras or MMC's...and so you might want to reconsider your assumptions, and your assumption of omnipotence.