Thin blue line

The "thin blue line" is a term that typically refers to the concept of the police as the line between law-and-order and chaos in society.^[1] The "blue" in "thin blue line" refers to the blue color of the uniforms of many police departments.

The phrase originated as an allusion to The Thin Red Line incident during the Crimean War in 1854, wherein a Scottish regiment—wearing red uniforms—famously held off a Imperial Russian Army cavalry charge. Its use referring specifically to the police was popularized by Los Angeles Police Department Chief William H. Parker during the 1950s; author and police officer Joseph Wambaugh in the 1970s, by which time "thin blue line" was used across the United States; and Errol Morris's documentary The Thin Blue Line (1988). In recent years, the symbol has also been used by the Blue Lives Matter movement in the United States, which aims to show solidarity with the police, and a number of far-right movements in the U.S., particularly after the Unite the Right rally in 2017.