Attenuation of the Taint

Attenuation of the Taint

Independent source and inevitable discovery, covered above, both argue that the government's evidence reached it, or would have reached it, through a lawful route. Attenuation, the third exception built on causation, concedes that the violation led to the evidence and asks whether the link has grown so weak that suppression would no longer accomplish anything. In Utah v. Strieff the Court described the doctrine this way: evidence is admissible when the connection between the unconstitutional police conduct and the evidence is remote or has been interrupted by some intervening circumstance, so that the interest protected by the violated guarantee would not be served by suppression.¹ The idea is older than that formulation. In Nardone v. United States the Court accepted that sophisticated argument can usually trace some causal thread between an illegal wiretap and the government's proof, and observed that as a matter of good sense the connection may become "so attenuated as to dissipate the taint."² Wong Sun v. United States later gave the inquiry its working question: whether the evidence was come at by exploitation of the illegality or instead by means sufficiently distinguishable to be purged of the primary taint.³

Three factors, drawn from Brown v. Illinois and applied in Strieff, structure the answer. They are the temporal proximity between the illegality and the discovery of the evidence, the presence of intervening circumstances, and the purpose and flagrancy of the official misconduct.⁴ The Court singles out the third as particularly significant, yet the factors are weighed together rather than tallied one by one. The reason lies in what exclusion is for. The rule exists to deter future violations by denying police any benefit from exploiting one, and the Court treats suppression as a last resort that applies only where its deterrence benefits outweigh its substantial social costs.⁵ The cost of suppression stays the same wherever the evidence sits on the causal chain, because a reliable item of proof is lost and a possibly guilty defendant goes free. The deterrent payoff does not stay the same. Time and intervening events show how far the chain has stretched, which tells a court whether an officer could have counted on the violation to produce the evidence, and flagrancy shows how much the conduct needs deterring. Each factor measures a different way the deterrent value can drain away, so any one of them can mislead when read alone.

Attenuation can arrive by two routes, and the second is easy to overlook. The first is remoteness, where the causal connection is too stretched to justify exclusion. The second applies even when the connection is direct, if the interest protected by the violated guarantee would not be served by suppression.⁶ The Court illustrated the second route in New York v. Harris, where an illegal warrantless arrest in the suspect's home was followed by a statement taken outside the house. The warrant requirement for in-home arrests protects the home, and everything incriminating that police gathered inside had already been excluded, so suppressing the later statement would add nothing to the purpose of the rule that was violated.⁷

Wong Sun itself supplies a matched pair arising from one episode of police misconduct. Toy was questioned in the immediate aftermath of the illegal entry: six or seven officers broke his door and followed on his heels into the bedroom where his wife and child were sleeping, and he was almost at once handcuffed and arrested. The Government argued that his statements were an intervening independent act of free will, and the Court rejected the argument, holding it unreasonable to infer that a response made in those circumstances was free enough to purge the taint of the unlawful invasion.⁸ Wong Sun's own later statement differed on the points that matter. After his unlawful arrest he was arraigned and released, and several days later he returned to the police station on his own initiative to make incriminating statements, so the Court held that the connection between the arrest and the statement had become so attenuated as to dissipate the taint.⁹ Time had passed, the coercive setting of the arrest was gone, and the decision to speak was his own, so each of those facts weakened the link between the violation and the evidence.

The modern application comes from Strieff. An officer watching a suspected drug house stopped Strieff as he left, without reasonable suspicion, asked for identification, and learned from a dispatcher that Strieff had an outstanding arrest warrant. The officer arrested him on that warrant, searched him incident to the arrest, and found methamphetamine and drug paraphernalia.¹⁰ The Court weighed the three factors and found attenuation even though they did not all point the same way. Temporal proximity favored suppression, since the drugs turned up only minutes after the stop. The intervening-circumstance factor strongly favored the State, because the warrant was valid, predated the stop, and was unconnected to it, which made the arrest a ministerial act the warrant itself compelled. The flagrancy factor also favored the State, because the officer's errors in judgment were at most negligent and fell short of a purposeful or flagrant violation.¹¹ Students lose this issue when they treat a short interval between the illegality and the evidence as decisive, because the search in Strieff followed the stop by minutes and the evidence was still admitted. The Court also rejected the Utah Supreme Court's view that attenuation reaches only a defendant's own free-willed acts, such as a confession or a consent. The doctrine examines the causal link between the government's unlawful act and the evidence, and that link often has nothing to do with what the defendant did.¹²

Because the doctrine is a judgment about exploitation, reasonable weighing can diverge. The dissent in Strieff reached the opposite result on the same factors. It reasoned that the officer ran the warrant check immediately as part of an investigative stop, that finding a warrant was no intervening surprise given how many outstanding warrants the jurisdiction carried, and that the stop was calculated to turn up evidence.¹³ The majority, for its part, acknowledged that evidence of a dragnet practice of stops made to harvest warrant hits could change how the factors come out.¹⁴ The inquiry therefore asks one question, whether the police exploited the illegality to get the evidence, and the factors are the evidence on that question. The sections that follow take them in the order the Court lists them, beginning with temporal proximity.

Temporal Proximity

The first of the three attenuation factors asks how closely the evidence followed the illegality. In Utah v. Strieff the Court framed it as the "temporal proximity" between the unconstitutional conduct and the discovery of the evidence, meaning how soon after the violation the police obtained what the prosecution now wants to use.¹⁶ The reason time matters comes from what an unlawful seizure does to the person subjected to it. Pressure, fear, and disorientation are strongest while the intrusion is still unfolding, and they fade as time passes and the person is released from police control. A response given in the immediate aftermath is therefore the most likely to be a product of the violation. It is also the response that exclusion most needs to reach, because officers who expect an instant statement to be suppressed gain nothing by exploiting the violation to get one.

Wong Sun v. United States places both ends of that scale inside one episode of police misconduct. Toy spoke while the invasion was still underway: six or seven officers had broken his door and followed him into the bedroom where his wife and child were sleeping, and he was almost immediately handcuffed and arrested, so the Court found it unreasonable to infer that his response was free enough to purge the taint.¹⁷ Wong Sun's own statement came after his unlawful arrest, an arraignment, and release on his own recognizance, and he returned to the police station several days later on his own initiative to make it, so the Court held that the connection between the arrest and the statement had become so attenuated as to dissipate the taint.¹⁸ The days that passed carried weight only together with what they allowed to change. By the time Wong Sun spoke, the coercive setting of the arrest had ended and the decision to return was his own.

Because the factor measures how an interval interacts with the circumstances around it, time is relevant without being decisive, and the error can run in either direction. A lapse of time does not cure a violation when the custody that followed it continues without a break. In Dunaway v. New York the Court held that a confession given after a period of continuous custody following an illegal arrest should be suppressed, even though the suspect had received Miranda warnings.¹⁹ A short interval, for its part, does not condemn the evidence. The drugs in Strieff were found only minutes after the unlawful stop, and the Court counted that against the State, since its precedents decline to find that the factor favors attenuation unless "substantial time" elapses.²⁰ The evidence was nonetheless admitted, because the discovery of a valid, unconnected arrest warrant and the officer's at most negligent conduct outweighed the close timing.²¹ Students lose this factor when they treat the passage of time alone as settling attenuation, whether the interval is minutes or days, because time only shows how likely it is that the evidence is a product of the violation, and the other two factors test the same question from different angles.

The next factor turns from how long the interval lasted to what happened inside it.

Intervening Circumstances

The second attenuation factor examines what happened inside the interval that temporal proximity measured. An intervening circumstance is an independent event that falls between the illegality and the discovery of the evidence and supplies its own explanation for how the evidence came to light.²³ The factor carries weight because attenuation asks whether the police got the evidence by exploiting the violation, and an event the police did not create can take over as the real reason the evidence surfaced. When that happens, suppression adds little deterrence against the earlier violation, since the police could not have counted on the event when they acted. Suppression would also protect the defendant from an arrest or discovery that was lawful in its own right.

The standard example is Utah v. Strieff. An officer stopped Strieff, learned that a valid arrest warrant was outstanding against him, arrested him on that warrant, and found methamphetamine and drug paraphernalia in a search incident to the arrest.²⁴ For purposes of decision the Court took the stop to be unlawful, because the State conceded that the officer lacked reasonable suspicion.²⁵ The Court held that discovering the warrant was an intervening event that broke the causal chain between the stop and the drugs.²⁶ Three features of the warrant carried that holding: it was valid, it predated the officer's investigation, and it was entirely unconnected with the stop.²⁷ Those features made the arrest a ministerial act, meaning one the officer had no discretion to decline, because a warrant is a judicial mandate and the officer has a sworn duty to carry it out.²⁸ Once the arrest was lawful, the search incident to it was lawful too. The stop was nonetheless a but-for cause of the discovery, since without it the officer would never have learned that the warrant existed.²⁹ The Court found attenuation anyway, which shows that the factor asks whether an independent source of lawful authority intervened, and that a but-for link settles nothing by itself.

The two qualifiers in that description, preexisting and unconnected, each do separate work. A warrant that already existed when the stop occurred was issued for reasons that have nothing to do with the stop, so the stop did not create the officer's authority to arrest and only revealed it. A warrant the police obtain afterward, on the strength of what the stop produced, fails both tests, because the police generated it and it carries the same taint as its source. The incentive problem is easy to see: if paper created out of an illegal stop counted as intervening, officers could launder any violation by following it with one more official step. Students lose this factor when they treat any later event as intervening, because preexisting and unconnected are what make a warrant independent.

Strieff also settles that the intervening event need not be something the defendant did. The Utah Supreme Court had read the attenuation cases to cover only a defendant's own free-willed act, such as a confession or a consent, and the Court disagreed, because attenuation examines the causal link between the government's unlawful act and the evidence, and that link often has nothing to do with the defendant.³⁰ Free-willed acts remain a recognized way to break the chain. In Wong Sun v. United States the defendant, after an unlawful arrest, an arraignment, and release on his own recognizance, returned to the police station several days later on his own initiative to make incriminating statements, and the Court held the taint dissipated.³¹ Courts likewise hesitate to suppress the testimony of a third-party witness, because the witness's own decision to testify usually breaks the chain even when the police found the witness only through an illegal search.³² Whether the break is a person's choice or an independent legal event such as a warrant, the common feature is a separate cause that did not come from the police illegality.

The same Wong Sun decision supplies the contrast case, in which nothing intervened. Toy made statements in his bedroom in the immediate aftermath of an unlawful entry, and those statements led the police to Yee, from whom narcotics were taken. The prosecutor candidly acknowledged that the drugs would not have been found except for Toy's help, and the Court held that the narcotics were come at by exploiting the illegality and could not be used against Toy.³³ Both Wong Sun and Strieff involve but-for causation, so that link cannot be what separates them. In Strieff a lawful event with its own legal force, the warrant, carried the officer to the evidence. In Wong Sun the police reached the narcotics by following the leads that the illegality itself had produced.

This factor was also where the Strieff Justices parted ways. The dissent would have held that the warrant check was no intervening circumstance at all, because the officer ran it immediately as part of an investigative stop, and finding a warrant was no surprise in a jurisdiction with a large backlog of outstanding warrants.³⁴ The majority gave the warrant's independence full weight and counted the factor strongly in the State's favor.³⁵ Because the factor turns on independence, it is best run as a short series of questions before it is weighed against the other two.

Flagrancy of Misconduct

The third attenuation factor turns from the timeline and the intervening event to the police conduct that started the chain. It asks about the purpose and flagrancy of the official misconduct, meaning whether officers violated the Constitution deliberately to get evidence, or in obvious and systematic disregard of it, or instead made an honest mistake.³⁷ In Utah v. Strieff the Court took the factor from Brown v. Illinois and singled it out as "particularly" significant among the three.³⁸ The emphasis follows from what the exclusionary rule is for. The rule's sole purpose is to deter future Fourth Amendment violations, and it applies only when the deterrence benefits outweigh its substantial social costs.³⁹ The third factor carries that cost-benefit logic into attenuation by favoring exclusion only when the misconduct is most in need of deterrence, which is to say when it is purposeful or flagrant.⁴⁰

The mechanism behind that weighting explains why two unlawful stops can come out differently depending on what the officer was doing. Suppression can deter only officers who choose their methods with an eye to whether the resulting evidence will be usable. An officer who deliberately stops people with no basis, expecting something to turn up, is making exactly that choice, and the prospect of losing the evidence gives that officer a reason to choose differently. An officer who misjudges in good faith whether the facts justified a stop was not weighing any such consequence, so suppression adds little deterrence while still costing the prosecution reliable proof. Treating flagrancy as a factor also keeps attenuation from becoming a loophole, because without it any independent event after a deliberate violation, such as the discovery of a warrant, could launder the violation.

The Court has tied the exclusion calculus to culpability in exactly these terms. It has said that the justification for exclusion varies with the culpability of the police conduct and that an assessment of flagrancy is an important step in the calculus.⁴¹ The history supports the point, because the abuses that produced the rule involved intentional and patently unconstitutional conduct. In Weeks v. United States officers broke into a home, took incriminating papers, and returned with a marshal to take more, although they had no warrant and could not have obtained one.⁴² Herring v. United States applied the same reasoning to the opposite kind of error, an arrest made on a warrant that had been recalled months earlier but still sat in a database through negligent bookkeeping, and held that isolated negligence of that kind does not call for exclusion.⁴³ A later section develops Herring in full. It appears here only to show that police culpability drives the deterrence calculus.

Applied to the facts of Strieff, the factor favored the State. Officer Fackrell had made two good-faith mistakes. He had not seen when Strieff entered the suspected drug house, so he lacked a sound basis for concluding that Strieff was a short-term visitor who might have just completed a drug transaction, and he should have asked Strieff whether he would talk instead of demanding that he do so.⁴⁴ The Court concluded that these were errors of judgment falling well short of a purposeful or flagrant violation of Strieff's rights.⁴⁵ That finding, together with the valid preexisting warrant, outweighed the close timing between the stop and the discovery of the drugs, and the evidence came in.⁴⁶

The dissent read the same stop differently, which shows where the real dispute over this factor lies. It stressed that the officer's sole reason for the stop was investigative, since he wanted to learn whether drug activity was going on in the house Strieff had just left, and it concluded that the violation was calculated to procure evidence as part of an expedition in the hope that something would turn up.⁴⁷ The majority did not treat that investigative aim as enough. A desire to investigate describes almost every stop, lawful or not, so if it alone made a violation purposeful, the factor would almost never favor the State. On the majority's account, what mattered was that the officer's errors were good-faith misjudgments about the facts and about how to approach Strieff, with no sign of a deliberate plan to obtain evidence by violating the Fourth Amendment.⁴⁸

The factor cuts the other way when the misconduct is deliberate, systematic, or built to exploit the violation. Strieff itself left that door open. Responding to the worry that police would run dragnet stops to harvest warrant hits, the majority said that such conduct would expose officers to civil liability under 42 U.S.C. § 1983 and that the Brown factors already account for purpose and flagrancy, so evidence of a dragnet practice could change how the factors come out.⁴⁹ Courts likewise ask how flagrantly officers violated the Fourth Amendment, and whether they used illegally seized evidence to advance their investigation.⁵⁰

Because the factor measures culpability, it has to be kept apart from the existence of the violation. Every attenuation question begins with an established or assumed violation, and in Strieff the State conceded that the stop lacked reasonable suspicion, so the factor cannot be asking whether the Fourth Amendment was broken.⁵¹ The common error is to equate the violation itself with flagrancy, when the question is how culpable the violation was. The factor also does not operate alone. Strieff weighed it together with temporal proximity and intervening circumstances, and Wong Sun lists flagrancy as one of three considerations, so strong flagrancy can outweigh an intervening event and weak flagrancy can outweigh close timing, yet neither decides the issue by itself.⁵²