Whig Ideals
Now we know the story of the colors, but that still begs the question: Why did our founders choose Whig colors for their uniforms?
American revolutionaries were, of course, British citizens until the United States declared their independence. And so they identified closely with British politics. The two main British parties of the day were Tories and Whigs.
A quick look at the principles of the Whigs - particularly the "radical Whigs" - shows us why American patriots chose their colors and their ideals.
Religious liberty - unlike the rest of the western world at the time, radical Whigs actually were in favor of allowing dissenters from the state religion. Though they were anti-Catholic, their opposition was rooted in the fact that the Catholic church of the day was political and absolutely quashed all religious dissent.
Constitutionalism - at a time when nearly all nations believed in the divine right of kings to dictate however they wished, radical Whigs instead said that kings must be confined to constitutional limits.
Representation in government - radical Whigs espoused the new idea of Parliament having supremacy over the king. The representatives of the people, they said, should have more power than a single monarch.