You're saying offshore wind farms would prevent the US from detecting an intercontinental attack crossing the ocean?
Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn
https://en.wikipedia.org/wiki/R%27lyeh
From where else would an enemy be able to attack? There's two options: ocean or space.
Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn
https://en.wikipedia.org/wiki/R%27lyeh