Prior to the 2000 presidential election, there was no universally recognized color scheme to represent political parties in the US. Color-based schemes became widespread with the adoption of color television in the 1960s and nearly ubiquitous with the advent of color in newspapers. A three color scheme — red, white and blue, the colors of the U.S. flag — makes sense, and the third color, white, is useful in depicting maps showing states that are „undecided” in the polls and in election-night television coverage.
Early on, the most common—though again, not universal—color scheme was to use red for Democrats and blue for Republicans. This was the color scheme employed by NBC—David Brinkley famously referred to the 1984 map showing Reagan’s 49-state landslide as a „sea of blue”, but this color scheme was also employed by most newsmagazines. CBS during this same period, however, used the opposite scheme—blue for Democrats, red for Republicans. ABC was less consistent than its elder network brothers; in at least two presidential elections during this time before the emergence of cable news outlets, ABC used yellow for one major party and blue for the other. As late as 1996, there was still no universal association of one color with one party.
But in 2000, for the first time, all major media outlets used the same colors for each party: Red for Republicans, blue for Democrats. Partly as a result of this first-time universal color-coding, the terms Red States and Blue States entered popular usage in the weeks following the 2000 presidential election. Additionally, the closeness of the disputed election kept the colored maps in the public view for longer than usual, and red and blue thus became fixed in the media and in many people’s minds. Journalists began to routinely refer to „blue states” and „red states” even before the 2000 election was settled. After the results were final, journalists stuck with the color scheme, such as The Atlantic’s cover story by David Brooks in the December 2001 issue entitled, „One Nation, Slightly Divisible.” Thus red and blue became fixed in the media and in many people’s minds despite the fact that no „official” color choices had been made by the parties.
The choice of colors in this divide is counter-intuitive to many international observers, as throughout the world, red is commonly the designated color for parties representing labor, communist, and/or liberal interests, which in the United States would be more closely correlated with the Democratic Party. Similarly, blue is used in these countries to depict conservative parties, which in the case of the United States would be a color more suitable for the Republicans.