Today, I learned that:
Old sayings are not always true. It may still be so that in the dark all cats still seem to be grey, but do you know why the American political parties are assigned with the colours red for the republican party and blue for the democratic party? It has not always been like that, as you will see below:
If you live in Europe, you are accustomed to the designation of the blue colour for right-wing parties and red for left-wing parties. Red has been associated with revolutionary movements during centuries, already present during the French revolution 1789. (I remember a phrase we learned in school to get the colours of the French flag in correct order: ‘Blod har runnit’ (“Blood has flown”), with b for blå (blue), h for (h)vit (white), and r for röd (red)). But why is it the other way in USA, considering that the republicans normally are to the right of the democrats, politically?

This NBC map from 1980 shows blue for Ronald Reagan, red for Jimmy Carter and yellow for uncalled states. Photo by Youtube.
It all started on November 2, 1976, when the American TV network NBC first presented a forecast of whom would win the presidential election, Gerald Ford or Jimmy Carter. The states where the republican party would win were lit in blue and the states with majority for the democratic party were red, something that NBC kept also in 1980, as you can see in the picture above. But from that point on, there was no general rule, which party would be blue and which one would be red was not a consistent choice, the different TV networks chose whichever colour they wanted. Reference 2 below has a deep discussion about the reasons, including also ‘r(ed)=r(epublican)’, but it seems that both parties for a long time used blue internally and attributed red to their opponent.
The current arrangement with blue for the republican party and red for the democratic party was eventually unanimous in year 2000, when George W Bush defeated Al Gore.
… That’s what I learned in school!
Refs.:
1: https://en.wikipedia.org/wiki/Red#Use_by_political_movements
2: http://www.smithsonianmag.com/history/when-republicans-were-blue-and-democrats-were-red-104176297/