Why is red for Republicans and blue for Democrats?

The words used often by Republicans and Democrats at the

When Republicans Were Blue and Democrats Were Red

TRT World on X: Red is for Republican and blue is for Democrat

What Painted Us So Indelibly Red and Blue?

Red States Outnumber Blue for First Time in Gallup Tracking

50 Years of Electoral College Maps: How the U.S. Turned Red and

California's 2018 'blue wave' followed by 2020 GOP red riptide

9 out of 10 midterm races won by Hays County Democrats

Democrats' Long Goodbye to the Working Class - The Atlantic