As Caroline Weber theorizes in her amazing book, Queen of Fashion, the vogue du jour contained greater meaning and had a greater effect in the 18th century than it does today. Weber goes as far to hypothesize that it was Marie Antoinette's wardrobe that had a monumental effect in her fall from grace and gives great evidence to support her theory. On the other side of the channel, Georgiana was just as much of a fashion icon and her influences had similar effects in society. Fashion played a significant part in politics as well. In a time where television was not there to force politics into the faces of the countrymen, fashion, and more specifically color.
So what palette was was appropriate for your wardrobe?
If you were a supporter of the Whig party, you could show your support in ensembles of blue and buff. These colors graced the uniforms of the American revolutionaries and were adopted by the Whigs who commiserated to the colonists' plight under King George.
If your sentiments tended to favor the Tory party, then another fashionable color option was laid before you. Green was their color of choice and was publicized in portraits of loyal Tories such as Banstre Tarleton.