I don't think there was any real picking involved on the part of the parties... Election maps would use red and blue, but that was a very intermittent thing to look at (once every four years for most people; voter turnout in the US was abysmally low, and who knows how many voters actually watched the results with interest). And each network would kinda randomly assign them to each party, without even agreement over which is which from one network to another. And then it finally settled into consistency in 2000.

https://en.wikipedia.org/wiki/Red_states_and_blue_states#Con...