The use of colors for identification purposes goes back deep into history

TEd's digression notwithstanding, the Romans *did have political color connections. The four major factions in the Games were the Reds, the Blues, the Greens and the Whites. Originally they were four independent and equal groups and, depending on who was the emporers favorite, political factions following them. Later on two of them (Green and White, I believe) became subsidiary to the other two. Whether this is in any way the origin of Red = left wing, Blue = right wing I don't know.