Weeks v. United States: The Origin of the Federal Exclusionary Rule

Supreme Court ruling on excluding illegally obtained evidence

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Weeks v. U.S. was a landmark case that laid the basis for the exclusionary rule, which prevents illegally obtained evidence from being used in federal court. In its decision, the court unanimously upheld Fourth Amendment protections against unwarranted searches and seizures.

Fast Facts: Weeks v. United States

  • Case Argued: Dec 2—3, 1913
  • Decision Issued: February 24, 1914
  • Petitioner: Fremont Weeks
  • Respondent: United States
  • Key Questions: Could the items obtained without a search warrant from Mr. Week’s private residence be used as evidence against him, or was the search and seizure without a warrant a violation of the Fourth Amendment?
  • Unanimous Decision: Justices White, McKenna, Holmes, Day, Lurton, Hughes, Van Devanter, Lamar, and Pitney
  • Ruling: The Court held that the seizure of items from Weeks' residence directly violated his constitutional rights, and also that the government's refusal to return his possessions violated the Fourth Amendment.

Facts of the Case

In 1911, Fremont Weeks was suspected of transporting lottery tickets via mail, an offense against the Criminal Code. Officers in Kansas City, Missouri, arrested Weeks at his work and searched his office. Later, officers also searched Weeks' home, seizing evidence including papers, envelopes, and letters. Weeks was not present for the search and officers did not have a warrant. The evidence was turned over to the U.S. Marshalls.

Based on that evidence, the Marshalls conducted a follow-up search and seized additional documents. Prior to the court date, Weeks’ attorney petitioned the court to return the evidence and to prevent the district attorney from using it in court. The court denied this petition and Weeks was convicted. Week’s attorney appealed the conviction on the basis that the court had violated his Fourth Amendment protection against illegal searches and seizures by conducting an unwarranted search and by using the product of that search in court.

Constitutional Issues

The main constitutional issues argued in Weeks v. U.S. were:

  1. Whether it is legal for a federal agent to conduct an unwarranted search and seizure of a person’s home, and
  2. If this illegally obtained evidence can be used against someone in court.

The Arguments

Weeks’ attorney argued that officers had violated Weeks’ Fourth Amendment protections against unreasonable searches and seizures when they entered his home without a warrant to obtain evidence. They also argued that allowing illegally obtained evidence to be used in court defeats the purpose of the Fourth Amendment.

On behalf of the government, attorneys argued that the arrest was based on sufficient probable cause. The evidence uncovered in the search served to confirm what the officers had suspected: Weeks was guilty and the evidence proved that. Therefore, the attorneys reasoned, it should eligible to be used in court.

Majority Opinion

In a decision delivered by Justice William Day on February 24, 1914, the court ruled that the search and seizure of evidence in Weeks' home violated his Fourth Amendment right. Fourth Amendment protections apply to someone "whether accused of crime or not,” according to the Court. Officers needed a warrant or consent to search Weeks' home. The federal government also violated Weeks' Fourth Amendment protections when the court refused to return evidence seized during an unreasonable search.

In finding that the search was illegal, the court rejected one of the government's main arguments. The government's attorneys had attempted to show the similarities between Adams v. New York and Week's case. In Adams v. New York, the court ruled that evidence incidentally seized while conducting a legal, warranted search may be used in court. Since officers had not used a warrant to search Weeks' home, the court refused to apply the ruling reached in Adams v. New York.

The Justices ruled that the illegally seized evidence was "fruit from the poisonous tree." It could not be used in a federal court. Allowing the district attorney to use such evidence to convict Weeks would violate the intent of the Fourth Amendment.

In the majority opinion, Justice Day wrote:

The effect of the Fourth Amendment is to put the courts of the United States and Federal officials, in the exercise of their power and authority, under limitations and restraints as to the exercise of such power and authority, and to forever secure the people, their persons, houses, papers, and effects, against all unreasonable searches and seizures under the guise of law.

The Court reasoned that allowing submission of illegally obtained evidence actually encouraged officers to violate the Fourth Amendment. In order to deter violations, the court applied the "exclusionary rule." Under this rule, federal officers who conducted unreasonable, unwarranted searches could not use the evidence they found in court.

The Impact

Prior to Weeks v. U.S., federal officers were not punished for violating the Fourth Amendment in pursuit of evidence. Weeks v. U.S. gave the courts a means of preventing unwarranted intrusions on a person’s private property. If illegally obtained evidence could not be used in court, there was no reason for officers to conduct illegal searches.

The exclusionary rule in Weeks only applied to federal officers, which meant that illegally obtained evidence couldn’t be used in federal courts. The case did nothing to protect Fourth Amendment rights in state courts.

Between Weeks v. U.S. and Mapp v. Ohio, it was commonplace for state officers, unbound by the exclusionary rule, to conduct illegal searches and seizures and hand the evidence to federal officers. In 1960, Elkins v. U.S. closed that gap when the court ruled that the transfer of illegally obtained evidence violated the Fourth Amendment.

Weeks v. U.S. also laid the groundwork for Mapp v. Ohio in 1961, which extended the exclusionary rule to apply to state courts. The rule is now considered a fundamental element of Fourth Amendment law, providing the subjects of unreasonable searches and seizures a unified manner of recourse.

Weeks v. U.S. Key Takeaways

  • In 1914 the court ruled unanimously that evidence obtained through an illegal search and seizure could not be used in federal courts.
  • The ruling established the exclusionary rule, which prevents the court from using evidence that officers uncover during an illegal search and seizure.
  • The exclusionary rule only applied to federal officers until Mapp v. Ohio in 1961.


  • Root, Damon. "Why Courts Reject Illegally Obtained Evidence." Reason, Apr. 2018, p. 14. General OneFile.http://link.galegroup.com/apps/doc/A531978570/ITOF?u=mlin_m_brandeis&sid=ITOF&xid=d41004ce.
  • Weeks v. United States, 232 U.S. 383 (1914).
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Spitzer, Elianna. "Weeks v. United States: The Origin of the Federal Exclusionary Rule." ThoughtCo, Aug. 27, 2020, thoughtco.com/weeks-vs-u-s-4173895. Spitzer, Elianna. (2020, August 27). Weeks v. United States: The Origin of the Federal Exclusionary Rule. Retrieved from https://www.thoughtco.com/weeks-vs-u-s-4173895 Spitzer, Elianna. "Weeks v. United States: The Origin of the Federal Exclusionary Rule." ThoughtCo. https://www.thoughtco.com/weeks-vs-u-s-4173895 (accessed March 28, 2023).