How did Star Trek know?

During the run of the original Start Trek they had an episode where Kirk and Spock end up on a strange planet (naturally) and stumble upon a people that resembled the United States fighting against the Chinese. One can see the flag, Declaration of Independence and so on. The episode was panned by the critics but my point is they foresaw the future fight and the loss by the United States. This clip is kind of choppy but it was the best I could find. The writers of science fiction again and again manage to predict the future, and Gene Rodenberry was one of the best,

scotty
beam me up a cold beer!

ray