US wind farms are 30 miles from the coast at most? No country is attacking that under some plausible deniability and it not being seen as an act of war.There are more important power lines further from civilisation running through rural areas in the US. These are not fiber cables a 1000 miles from the coast.

Gas generators can be spun up to provide megawatts in seconds btw. With less than a quarter of the grid being renewable, intermittency is not an issue. Grids are built with resilience in mind (or at least should be...).