The Exclusionary Rule: How Fourth Amendment Violations Can Lead to Tossed Evidence

The Fourth Amendment declares the right to be secure from unreasonable searches and seizures. Evidence obtained through warrantless searches by police may be deemed inadmissible at trial, referred to as the "fruit of the poisonous tree," a concept central to the exclusionary rule.

What the Fourth Amendment Says

The Fourth Amendment of the U.S. Constitution states:

"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

Frequently Asked Questions

In criminal law, the outcome of a trial can often hinge on excluding illegally obtained evidence. 

Below, we answer a few of the most frequently asked questions about the exclusionary rule and the admissibility of evidence in a criminal trial. 

Why is the exclusionary rule important?

The exclusionary rule helps to deter police misconduct, as the U.S. Supreme Court determined in Mapp v. Ohio. It also provides a remedy for violations of the Fourth Amendment and other constitutional rights important to criminal cases.

The exclusionary rule also applies to self-incrimination under the Fifth Amendment and violations of the right to counsel under the Sixth Amendment. These rights, emphasized in Miranda v. Arizona, are essential for those accused of a crime. 

What happens if the evidence is obtained illegally?

Unless one of the exceptions to the rule applies, the evidence will not be admissible at trial. For example, suppose the weapon in a murder case is found because of an illegal search. In that case, prosecutors cannot show it to the jury or use their knowledge of it as part of their case.

Furthermore, any additional evidence derived from the illegal search, such as a confession, will likely be excluded as the "fruit of the poisonous tree."

For example, let's say police told the defendant they found the murder weapon, and this led the defendant to confess to the crime. Courts will view the confession as tainted because it resulted from an illegally obtained weapon.

This doctrine stems from Wong Sun v. United States, where the Court excluded statements made by the defendant after his unlawful arrest and evidence of narcotics taken from a third party as a result of those statements. 

Can you raise exclusionary rule concerns after a criminal trial?

Defendants may file a motion to suppress evidence only before or during their criminal trial. In Stone v. Powell, the Supreme Court found that the costs of allowing challenges on appeal outweigh the minimal deterrent effect.

However, let's say a defendant raises a challenge during trial, and the judge denies it. In that case, on appeal, they can argue that the evidence shouldn't have been allowed in.

Is the exclusionary rule applicable at probation violation hearings?

No. In Pennsylvania Bd. of Probation and Parole v. Scott, the Supreme Court found the "social costs of allowing convicted criminals who violate their parole to remain at large are particularly high."

Is evidence excluded if the police fail to obtain a no-knock warrant?

Even if police officers have a valid warrant, other procedural rules require them to announce their presence before entering a residence, particularly for officer and resident safety. For example, an unannounced entry may result in a resident firing at officers if they mistake them for burglars. 

If the police officers violate the knock-and-announce rule, the Court will not automatically exclude the evidence collected. For example, if police officers execute a search warrant for drugs, announcing their presence may result in the destruction of evidence while the officers wait for permission to enter. Alternatively, they may enter unannounced if there is a person inside who is in danger.

In Hudson v. Michigan, the Court explained that the knock-and-announce rule protects interests in human life, property, and privacy. However, the rule has never protected a defendant's interest in preventing the government from seeing or taking evidence described in a warrant.

Does a change in the law render evidence inadmissible?

Generally, no. If an arrest or a search was valid when it took place, the evidence is admissible even if the statute is later invalidated.

Can a grand jury witness refuse to testify based on evidence from an unlawful search or seizure?

The exclusionary rule does not prohibit the use of illegally seized evidence in all proceedings. Under United States v. Calandra, a grand jury witness may still have to answer questions even if they're based on evidence obtained from an unlawful search and seizure.

History of the Exclusionary Rule

Weeks v. United States established the exclusion of evidence as a remedy for Fourth Amendment violations. Week's conviction was based on evidence seized from his home after two warrantless searches. This evidence consisted of private papers. 

The admission of illegally seized evidence would void the protection of the Fourth Amendment and render this amendment valueless.

The Court further expanded the exclusionary rule in Boyd v. United States after the defendant was compelled to produce his business papers. By forcing Boyd to produce the incriminating evidence, the Court likened this to a search and seizure and implicated a violation of the defendant's Fifth Amendment right against self-incrimination. 

Extending the Exclusionary Rule to the States

In Wolf v. Colorado, the Supreme Court clarified that safety from unreasonable searches and seizures was a fundamental right and, therefore, applicable to state officers by the Due Process Clause of the Fourteenth Amendment. However, the Court did not mandate applying the exclusionary rule in state courts.

Then, in Mapp v. Ohio, the Court overruled the Wolf decision, holding that "all evidence obtained by searches and seizures in violation of the Federal Constitution is inadmissible in a criminal trial in a state court." The exclusionary rule as a standard was now applicable in state or federal court.

Scope of the Exclusionary Rule

Technical or good faith violations can still lead to the exclusion of reliable evidence. The Court must balance the legality of police conduct and defendants' rights under the Constitution. 

The exclusionary rule protects a personal right against an illegal search. To prevent a blanket application to any criminal defendant, the Court in United States v. Padilla and Rakas v. Illinois found that only co-defendants with standing can contest the admission of evidence from a warrantless search.

For example, a co-defendant riding in the passenger seat of a car they own has standing to challenge an illegal search because of the property interest, even if they are not driving the car at the time of the search.

If the Court excludes evidence from a warrantless search, the government is only restrained from introducing it as proof of guilt. The government could bypass the exclusionary rule by requesting to introduce it as impeachment evidence to discredit a testifying defendant's credibility. 

Another way the prosecution can circumvent the exclusionary rule is to show that the evidence would have been inevitably discovered or demonstrate sufficient attenuation between the police misconduct and the evidence. For example, in Segura v. United States and Murray v. United States, an independent source provided information that officers used to secure a warrant after a prior illegal entry and search. So, the evidence was admissible. 

Exceptions to the Exclusionary Rule

When it comes to Fourth Amendment violations, there are four main exceptions to the exclusionary rule:

• Searches made during a lawful arrest

• Evidence found in plain view of an officer

• Searches made with the consent of the person or property owner

• "Good faith" reliance on a defective warrant

We discuss each of these exceptions below. 

Search Incident to a Lawful Arrest

When police arrest someone, they may search the person and the area immediately within the person's control without a warrant.  

For example, suppose police arrest a pickpocket after observing them take someone's wallet. In that case, they will search the person and anything attached to them or their body, such as a purse. This ensures the safety of the police officer from dangerous objects such as weapons.

The Court first outlined this exception in Terry v. Ohio, which permitted officers to frisk individuals for weapons by patting down their outer clothing. This was not considered a search under the Fourth Amendment. However, the Court expanded the scope in United States v. Robinson, finding that a search incident to a valid arrest is not limited to a frisk of the suspect's outer clothing, but a full search of the person is a reasonable exception.

Plain View

A police officer can seize evidence they see in the course of their lawful duties. For example, during a traffic stop, the officer may seize drugs they can see in the driver's backseat. This prevents the destruction of evidence and secures the scene for further processing. 

Additionally, in Coolidge v. New Hampshire, the defendant's wife showed officers several weapons in the home and offered to let them take them. The Court held that evidence found by inadvertent discovery may be seized under the plain view exception to the warrant requirement.

Consent

If someone voluntarily consents to a search, police do not need a warrant. This exception is particularly tricky if the defense challenges the voluntariness of the consent. So, the burden is on State prosecution or the United States Government in federal prosecutions to prove the consent was voluntary. 

Review courts, such as the Court of Appeals, will look at the totality of the circumstances. For example, if a suspect lives with their parents, either parent may consent to a search of their home. Or a joint occupant of a room can consent to a search, as decided in United States v. Matlock. 

"Good Faith" 

In United States v. Leon, the Court created an exception for evidence obtained as a result of officers' objective, good-faith reliance on a warrant issued by a detached and neutral magistrate, later found to be defective.

Judicial officers and magistrates rely on sworn affidavits submitted in conjunction with warrant applications to determine probable cause for warrants. If the warrant is later found deficient, that alone will not exclude evidence under the good faith exception. However, an inquiry will still occur to determine whether the error resulted from knowing or reckless falsity.

For example, search warrants are only issued after a showing of probable cause and must describe the person or premises being searched and the particular items being searched for. If the affidavit transposes an apartment number such as 23 instead of 32, an otherwise facially valid warrant will not result in the exclusion of evidence obtained. The exclusionary rule serves to deter deliberate, reckless, or grossly negligent conduct.

In Herring v. United States, a recalled warrant was not removed from a police database leading to the defendant's arrest. The evidence found in a search incident to the arrest was still admissible because the mistake was reasonable and an isolated instance of negligence attenuated from the arrest. 

Alternatives to the Exclusionary Rule

Several alternatives exist to the exclusionary rule. Illegal searches and seizures can lead to criminal action. While it is uncommon for officers to be prosecuted, they may still be subject to disciplinary measures.

More commonly, people who have been illegally arrested or invaded their privacy will seek civil remedies in the form of monetary damages. The Supreme Court has held that a right to damages for violating Fourth Amendment rights arises by implication and that this right is enforceable in federal courts.

However, law enforcement officers have the usual common-law defenses available to them, the most important of which is the claim of good faith. Officers are entitled to qualified immunity where clearly established law does not show that the search violated the Fourth Amendment. Or where officers had an objectively reasonable belief that a warrantless search later determined to violate the Fourth Amendment was supported by probable cause or exigent circumstances.