Julius Caesar was assassinated for wearing red boots. Barrack Obama was lambasted for wearing a tan suit. Purple is associated with royalty, white is associated with clergy, and gold is associated with superiority. Red and Blue have powerful meanings in America, and so does Green. Which colour is the most political in your opinion?
...Which is a bit disturbing because it is generally used to refer to bloodshed or might in battle - partially in a "let's honor the past" sort of way, but mostly in a "don't fuck with us" sort of way.
During the Golden Age of Piracy, pirates would fly a red flag to communicate no quarter. That meant that if anyone decided to fight back would be killed because they were not taking prisoners.
Imagine being a miserable English sailor months from home, broke af, and hungry, when you're out in the ocean about to head back and you see this pulling up:
Japanese budhist monks use black for their clothes as it simbolizes purity, or as black being the most pure color.
In very few instances, they may wear purple or gold, but that's due status and a latter addition.
In a funeral, only the deceased would wear white, I don't remember why though, but for a while wearing white was in bad taste.
Not a single color, but in Chinese tradition there were five colors of equal political significance corresponding to the Wuxing cycle of changes—black, red, cyan, white, and yellow. Each dynasty was associated with a color (with other associated traits), and was expected to be followed by one of two other colors (depending on whether the succession would be orderly or revolutionary).