In Praise of the Exclusionary Rule(Inside NACDL)

Is the exclusionary rule needed to deter illegal police searches?

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I was recently asked this question: Is the exclusionary rule needed to deter illegal police searches? Reams have been written pro and con on the inherent value of the exclusionary rule. Indeed, as far back as the early 20th century, a little more than a decade after the rule emerged in American jurisprudence, Benjamin Cardozo noted that the exclusionary rule had been the subject of so much debate that “little of value can be added.”1 But as circumstances evolve and the government’s technological capacity to snoop, search and seize increases, it is important to revisit the question of whether the rule serves as a deterrent to lawless behavior. For if ever there was a time when Americans need an effective bulwark against governmental overreaching and oppression, it is now.

To support the view that exclusion is a deterrent, it is useful to take a look at developments since the Supreme Court decided a case that was the focus of an earlier Inside NACDL column.2 The Supreme Court in January decided a case — United States v.Jones3 — that is sure to be the first of many that will test the limits of the government’s ability to use modern technology to invade individual privacy. The Court unanimously upheld the suppression of GPS tracking data, rejecting the government’s sweeping claim that it can track a person’s movements without spatial or temporal limitation, and without a warrant or any judicial oversight.

The idea that such surveillance could occur solely at the government’s discretion prompted Chief Justice John G. Roberts Jr. to ask in astonishment during oral argument whether, in the government’s view, the FBI could put GPS monitors on the cars of every member of the Supreme Court. The government’s answer was a resounding “yes.” Fortunately, for the future of privacy in a world in which technology now permits once unfathomable invasions of privacy, the Court’s decision was an equally resounding “no.”

How widespread was the use of tracking devices before the Court’s decision? The deputy solicitor general acknowledged that the federal government alone has been using GPS devices “in the low thousands annually.” Separate from that, state and local law enforcement authorities frequently employ GPS tracking devices — subjecting untold thousands to surveillance.

Was the Court’s invocation of the exclusionary rule, a venerable remedy that will soon celebrate its 100th anniversary in American jurisprudence, an effective tool to vindicate fundamental rights guaranteed by the Fourth Amendment? You bet it was. Within weeks, FBI General Counsel Andrew Weissmann said the ruling in United States v. Jones caused a “sea change” in law enforcement. Following the oral argument and in anticipation of the ruling, the FBI scrambled to ensure that the government had warrants for 3,000 active GPS tracking devices. After the decision, 250 of those tracked devices were shut down. Many may eventually be reactivated if there is legal cause — as they should be.

Federal use of GPS tracking devices is just the tip of the iceberg. No one knows how frequently states and localities have employed these devices, but a plethora of cases around the country suggest that local use of GPS devices is extensive.4 Just as federal law enforcement agencies responded to the decision by altering their practices, so will the states and localities. Scott Burns, executive director of the National District Attorneys Association, recently said, “I can say, anecdotally, that across the country, prosecutors now have to meet with law enforcement to prepare affidavits and warrants when they want to use a tracker.”5 

So the answer is an emphatic “yes!” The exclusionary rule does deter, and once again its power to rein in governmental abuse is vindicated.


  1. People v. Defore, 150 N.E. 585, 587 (N.Y. 1926).
  2. Norman L. Reimer, Will 2012 Be a Defining Year for Privacy in America?, The Champion, December 2011 at 7.
  3. United States v. Jones, 132 S. Ct. 945 (2012).
  4. For example, NACDL filed amicus briefs in two jurisdictions (New York and Ohio) in which GPS tracking, without any judicial authority, was routine. In People v. Weaver, a case that preceded the Jones decision, the New York high court prohibited the use of GPS tracking devices without a warrant on state constitutional grounds. In People v. Johnson, the Ohio Supreme Court remanded for further consideration in light of Jones.
  5. Kashmir Hill, How Many GPS Trackers Is the FBI Actually Using?, March 27, 2012, available at

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