thin blue line

By analogy with Thin Red Line. “Blue” refers to the color of the uniforms of many police departments.

the thin blue line

1. (colloquial, collective) The police.
   • 2005 March 27, Tony Thompson, Martin Bright, “Crime wave overwhelms thin blue line”, in The Observer‎, →ISSN:

     Crime wave overwhelms thin blue line [title]

   • 2010 October 13, Alan Travis, “The thinner blue line – police warning over 25% budget cut”, in The Guardian‎, →ISSN:

     It followed dire warnings from the police staff associations that the possible loss of up to 40,000 police jobs would mean "Christmas coming early" for criminals, and the "thin blue line" left too stretched to cope with the inevitable risk of social and industrial unrest.

2. A flag or symbol representing the police, commonly associated with the blue lives matter movement.
   • 2020 November 21, Michael Gold, “What Happened When a School District Banned Thin Blue Line Flags”, in The New York Times‎, →ISSN:

     “Obviously, you’ve seen caravans with the Trump flag in the back of pickup trucks and then the thin blue line,” Mr. DeMasi, a former police officer, said. “I think maybe people had a good intention, but it ended up giving the meaning of the thin blue line a black eye.”

• blue flu
• blue line
• green line
• red line
• single yellow line
• Thin Red Line