In an election-themed episode of the highly informative video series Today I Found Out host Daven Hisky explained how the resulting confusion of the 2000 Bush v. Gore Presidential election solidified the use of red and blue as the decided colors of the U.S. political parties on electoral maps.
So ubiquitous in today’s political discourse, many assume that the red state/blue state distinction has been around as long as we have had Republicans and Democrats. In fact, the opposite is true – the dichotomy is relatively young, having only become settled with the Presidential election of 2000. …By this election, NBC had settled on blue to represent states won by Democrats and red to designate those won by Republicans. … While we obsessed over hanging chads, the electoral system and Katherine Harris, television broadcasters repeated the red state, blue state mantra ad nauseum. By the time the Supreme Court crowned George W. Bush the 43rd President of the United States on December 12, 2000, in Bush v. Gore, the dichotomy was ingrained in the American psyche.