IIRC, the blue/red switcheroo occurred during the 1980 Presidential campaign when the three networks (all there was then) decided to depict the electoral map with states going for Jimmah Carter in blue, and states for Ronald Reagan in red.
John Chancellor or somebody said later the networks did not want the color red associated with the Democrat party because of its communistic associations (flags of USSR, China, North Vietnam) and felt red was more appropriate for the going-Republican southern states as it symbolized red clay & backwardness. True story.
Amazingly revealing. I had never heard that John Chancellor story. I do remember visiting the United States Military Academy at West Point and at that young age noticing the Blues in the Reds on the battle maps historically displaying troop movements and positioning. When the colors for the Democrats and Republicans came out as red and blue States, I immediately remembered my visit to the United States Military Academy at West Point and those Maps.
Another thing that I noticed was that the United States Military Academy at West Point, has many statues of many generals and not a few during the Civil War period. the Revelation I had as I walked around the grounds looking at the statuary Was that there were no confederate general statues even though they had been West Point graduates for the most part. Being raised in the south I never really thought about the Civil War in that context before. But the North and the South were enemies and sadly it was more than the old brother versus brother analogy. It was bloodlust and Kill Them All.