After the 2000 election, the color red became associated with Republicans, although the party has not officially adopted it. That election night, for the first time, all of the major broadcast networks used the same color scheme for the electoral map: states won by Republican nominee George W. Bush were colored red, and states won by Democratic nominee Al Gore were colored blue. Although the assignment of colors to political parties is unofficial and informal, they have come to be widely recognized by the media to represent the respective political parties.
Who knew that red only became the republican color in 2000.