It is common knowledge that the Democrats wave Blue and the Republicans the Red. But why, when blue is traditionally meant to represent traditional, nay conservative and red, rebellion? My supposition is that it all goes back to the revolution (1776). Since this country was founded on rebellion, revolution, it would make sense that the older party, more reminiscent of Europe, the Federalist party, later the Democrat party would wave the blue flag. Those standing steady, the Anti-Federalists, the Whigs, and their offshoot the Republican party are seen as the rebels.
In the rest of the world, the old way still holds; e.g. France (continental Europe) is blue; Britain is red. China and USSR were red, signifying the Communist revolution; European Union, the paragon of tradition, the latest iteration of the European Commission, is blue.
Essentially the American Revolution acted as a (-1) coefficient to this side of the Atlantic equation. Id est, up is down, black is white, cats mating with dogs (gratuitous Ghostbusters reference.) Even the Mounties wear red.
Noted exceptions: Cuba, but that can be explained by Cold War-era Communist Revolution, Soviet proxy-state status. Also there was the British wearing red on the American Revolution battlefield to camouflage blood from musket shots.
Disclaimer: this list is not exhaustive, as always, just whatever was top of mind prior to the composition of my postings.