Symbolically, the US is broken up into red states and blue states, and if we end up in another Civil War, those may well be the colors of the two major sides.
However, this is very recent, as many of you probably know. Beginning in 1976, red and blue were used on TV broadcasts to differentiate states on election night, but there was no consistency. One network might have the Democrats red and Republicans blue, another the opposite. After the 2000 election, the networks coordinated and began consistently our current color scheme.
I've wondered quite a bit about why the colors sorted out the way they
did. Blue is the traditional color for conservative parties, and red is normal
for the left. In fact, blue used to be more common to represent the
Republican Party because of its Civil War association with the Union. So how did the Republicans end up red?
Honestly, it could well have been just a random thing. According to the All-Knowing Wikipedia, journalist Tim Russert started using the terms "red state" and "blue state" while covering the 2000 election, and it has stuck. Maybe that's all there is to it.
On the other hand, the conspiracy theorist in me whispers that it could have been an intentional thing. If the Democrats were red, it would be too easy to just call them reds. Maybe journalists anticipated this and protected their own.
In any case, each side now has a permanent color to rally to, the beginnings of a flag, semi-permanent colors marking territories on our maps. This seems to have emerged out of a genuine increase in polarization, but at the same time, I wonder if, now commonplace, it doesn't also support that polarization by making what had been abstract and fleeting designations used only on election nights into permanent or semi-permanent representations.
Compared with economics and ideologies and cultures, this is a very small thing, but it makes it easier to imagine us as separate peoples, maybe even separate nations, and imagination has its own kind of power.