Why do left and right mean liberal and conservative?

During the election season the words left and right denote political affiliation more than spatial direction. But where do these associations come from?

The left hand has long been associated with deviance. The word “sinister” originally meant “to the left” in Latin. The word “left” comes from the Old English word lyft, which literally meant “weak, foolish.” To avoid the negative and superstitious associations of the left side, many languages used euphemisms for it. In Old English the left side was called winestra, which meant “friendlier.” In Greek it was called aristeros or “the better one.”

When did the political affiliation of these two common words arise? In fact, the association is not American at all. It originated during the French Revolution. In the 1790s, King Louis XVI  was fighting with the Legislative Assembly. Like our modern-day House of Representatives, seating in the French Legislative Assembly was arranged based on political affiliation. The King sat in front of the assembly. To his right sat the conservative Feuillants who backed the king and believed in a constitutional monarchy. To his left sat the liberal Girondists and radical Jacobins who wanted to install a completely democratic government. Oddly enough, in the U.S. House of Representatives the tables have turned: members of the Republican party sit to the left of the House Speaker and members of the Democratic party sit to his or her right.

It wasn’t until the early 20th century that Left and Right denoted political affiliation in Britain and the US, and the more politically loaded terms “leftwing” and “rightwing” were not widely used until after 1960 according to Google’s NGram viewer.

Read more at http://hotword.dictionary.com/leftright/#kb86f1jjtoRJvDHz.99