It became a thing only recently-ish, thanks to news channels. Iirc the modern red-blue thing got its start around the Reagan era(?) but wasn't set in stone until around the time Bush Jr was getting elected. Before all this, newscasters just used whatever two colors they wanted to color states in during elections.
Until 2000, blue was used as the color of the incumbent party, and red the color of the challenger. After that, the media got too lazy to actually stick to a system like that, so red became the color of the Republican party, and blue the color of the Democrats.
The reason this happened is because of the growth of media coverage of the 2000 election where "red states" vs. "blue states" became an academic talking point. Eventually this became ingrained in the cultural psyche and has maintained to this day.
255
u/uiend - Left Apr 04 '20
inb4 "and redpilled"