During the 1970s there was a big fight over nuclear power.
Environmentalists didn't want it around and were doing their level best to demolish it as a practice. The country was also hit hard by Opec around the same time. It was a daunting time in american history, but the nuclear industry fought back hard, with a PR push, information about certain environmentalists having soviet connections was also brought out which discredited the movement just enough for a big nuclear push.
The 1970s-80s would see america follow the french example and build nuclear powerplant's in every state in the union. A standard model was developed, new efficiencies and safe methods created, and the experement with Thorium a success.
Today around 80% of america's electricity comes from Nuclear but what if that push didn't happen what if america didn't go nuclear?