Incompetence incarnate. One of the staples of Mack Sennett's silent-movie comedies from World War I through the 1920s was a group of clumsily ineffective policemen known as the Keystone Kops (Keystone was the name of Sennett's film company). The Kops moved as a group, bumping into each other, driving their car in circles, and otherwise achieving nothing in the way of law enforcement but producing lots of movie mayhem. As a phrase to describe a group that accomplished nothing after lots of effort, “Keystone Kops” would suit them to a T.