In September of 1919, the police walked off the job and the city was engulfed in a riot. Order was restored eventually by the Massachusetts National Guard, acting under the authority of martial law. The riot seemed to demonstrate that police presence controlled social order and criminal behavior. Law enforcement administrators, politicians, the press, and many American people accepted this logic after the riot in Boston. Evidence, however, suggests that the riot was caused by other factors beyond the control of the police. These factors are examined in this article, and it is argued that social norms played a greater role than police activity in controlling crime. 33 references. (Author abstract)