Long Arm Of The Law Meaning

(idiomatic, almost always preceded by the) The influence or effectiveness of law enforcement institutions; law enforcement officers collectively.

Example: 1889, Wilkie Collins, The Legacy of Cain, ch. 60:
  It is my belief that I could have felt no greater dismay, if the long arm of the Law had laid its hold on me while he was speaking.
1979, "Pass the Buck," Time, 3 Sept:
  The long arm of the law does not protect banks the way it used to.
2008, Lisa Rein, "Jurisdictions Share Data on Ex-Offenders," Washington Post, 12 Sept. (retrieved 6 Spet. 2009):
  "Repeat violent offenders will hopscotch over state lines to avoid the long arm of the law," said Maryland Gov. Martin O'Malley.