Turncoats

A turncoat is a traitor, a disloyal member and supporter of a group, or political party, and a subscriber to the group’s cause and beliefs.

The Word Origin & History paragraph of Wikipedia says “the expression to turn one’s coat and change principles and party is recorded from 1565.” We had thought it came from the more dramatic and egregious act of an entire company of soldiers taking of their Redcoats and putting on the Bluecoats of the enemy army.