Going Through a Phrase Week

This week on Random Acts of Information we examine common American phrases.  Why?  Because it's fun.  First up - 'blue lights'.  Quick, what comes to mind?  Does it start with a 'K' ?   This phrase has absolutely nothing to do with bargains. No siree.  During the Revolutionary War a group called the New England Federalists  remained loyal to the crown.  According to one Commodore Decature said Federalists used blue lights to warn British ships of impending attack. Soooo until about the 1850's 'blue lights' meant 'traitors'.  And it sounds so innocuous!

Source: I Hear America Talking p.381