As I've understood it, the exclusionary rule is a prophylactic rule aimed to prevent the cultivation of illegal evidence collection by removing the utility of illegally-collected evidence through inadmissibility in court.

Another way to prevent illegal evidence collection would be through strong and fear-inducing punitive action.

The problem with the inadmissibility route (1) is that in certain cases, good evidence is thrown out. The limitations to the law that I've seen do not include any "if the evidence shows a grave crime, it must be admissible, despite illegal collection". It seems problematic that there can be blatant, undeniable evidence for heinous crimes, yet just because it was illegally attained, a blind eye must be turned and the criminal goes free.

One problem with the punitive route (2) is that it, to me, seems to go against the values of the US legal system. The way I see it, one can morally look at illegal actions done by a government official in two ways: (a) they are so important and have a hard job (esp. officers), so they should get more lenient punishments. (b) they are supposed to set an example and they have sworn an oath, when they break the law, it sends a message of hypocrisy and insecurity that breeds government hate and distrust.

Going with the (b) view, government officials should at least be given equally strong punishments, or stronger. It seems however, to my foreign and non-lawyer eyes, that the US is more in the (a) camp, meaning government officials should be given more lenient punishments. Given this assumption, route (2) would run contrary to at least one moral notion of the US legal system.

Another problem with route (2) is that it might wind up incarcerating or firing a lot of officers and agents, though some may say that is a good thing due to the nature of those officers and agents. The last problem that I can think of is that this system may be easy to exploit. If strong punitive action was taken against illegal evidence collection, yet it is still admissible, that leaves motivation to do it. So, officers may congregate and create a kind of group immunity to punitive action, with everyone swearing to each other to never testify against one another on matters of illegal evidence collection. This could then propel illegal evidence collection, due to there being no practical danger in doing it, since the majority of officers have each others backs. Investigaton would be done by officers or agents, and if they're in on it, then there's no chance. This would then propel illegal evidence collection, and it could maybe lead to graver violations of privacy during the collection, as the informal rules of "no testifying" would probably not include a bunch of clauses for when the privacy/legal violations were too serious to be allowed.

To me, the reasons I've given does make route (1) more favorable. However, I don't think I have figured out every reason that went behind the choice of (1) instead of (2). I am also not sure whether the reasons I've given are correct. One of my reasons was also based on an assumption that the US legal system holds the view contained in (b). So, what reasons did I get right/wrong, and what reasons did I miss?


After reading @Dale M's answer, I realize I forgot to specify I was talking about US jurisdiction, as I've only heard of this law in relation to the US. However, this led to a pretty good answer about whether or not countries in the West generally have an exclusionary rule or not. Interesting to see that, in the West at least, it seems to be pretty limited to the US.

4 Answers 4


The problem with Solution 2 is that government officials in the United States enjoy qualified immunity with respect to actions that they did while acting under color of law. It's not total immunity, but if they do things by the book, they cannot be prosecuted even if something goes wrong (even when doing things by the book, Police deal in very volatile situations and things can still go wrong because of an X factor to specific for the training manual to cover.).

In other cases, it may be because multiple officers are working the scene and Office A lied to Officer B about the situation. Consider Officer A pulls over a suspect and realizes it was someone who was suspected of a crime, but couldn't prove it. He calls for back up and Officer B arrives. Upon arriving on scene, Officer A tells B to search the trunk of the car despite the fact that A had not received consent from the suspect nor has a warrant, nor cause to make a search of a trunk of a vehicle. B makes the search and finds [the bloody knife/the stash of drugs/the smoking gun/the match to a child's shoe that was missing from the kidnapping scene/ insert other incriminating evidence]. Under system (2), since it was Officer B who made the illegal search, B would be liable for it, even though Officer A lied about having legal reason for a search of the trunk space.

But what's more... if the evidence is gonna be used anyway, what's to stop the cops doing it again? After all, there is very little recourse for those who are illegally searched to contest this in court (If I'm illegally searched and don't have anything on me, I have to take this to civil court, which is a different animal than Criminal Court and exposes me to broader Discovery... aka gives the cops free reign to search my property for a hell of a lot more illegal things.) or just sit back and count my 4th amendment rights (the section of the constitution protecting against unwarranted search and seizures) as worth less than the paper they're printed on. Oh, and by the way... that second word seizure... that means that they will be taking my property (or myself if they arrest me) and will not be giving it back for some time while they process it... if it's a legal to hold item (like my laptop that I do work on) that's going to make it harder for me to do my job which injures me further in lost business and income.

In other cases, it could be they have a warrant for a large item (a stolen big screen tv) and while searching for it, open my sugar bowel and find evidence of a crime unrelated to theft of the television (i.e. opening a baggie of weed). This is actually an illegal search because, unless I am a wizard, a Time Lord, or Mary Poppins, there is no reason why a container smaller than a big screen TV should ever be searched when looking for a Big Screen TV and the cops should logically see this as out of bounds of the search warrant.

The nature of this is damaging before the legality of the search can be determined, and because the search may have been out of scope of the warrant that was otherwise justified, the rule of making the evidence of a crime inadmissible was held in order to prevent LEOs from doing this because they could. This rule also started to take formation prior to the Revolutionary War. British Law had ruled against compelled confessions being inadmissible as evidence in 1769, a full six years before the Revolutionary war started (1775) and seven years before the publication of the Declaration of Independence (1776).

Now there are some exceptions that can get the evidence brought back in, such as plain view ("The suspect's vehicle is a pick up truck with an open bed, the murder weapon was lying in the bed covered in blood"), inevitable discovery ("We have developed evidence by other means that would have lead us to this evidence legally") and Exigent Circumstances ("We believed someone inside the property was in grave danger if we did not enter the property immediately and that's when we found a cache of stolen Big Screen TVs!) and Good Faith (the Warrant was authorized for the wrong street address of the target but we found the evidence of an unrelated crime in a place the warrant authorized us to search. Everything but the goofed up address was done by the book.).

  • There was a case in the USA where the police had a totally legitimate warrant to search the apartment of Mr X on the third floor of a house. Except nobody realised there were two apartments on the third floor and they went into the wrong one. Where they found an illegal gun. The search was legal.
    – gnasher729
    Dec 8, 2021 at 23:53
  • @gnasher729 Probably got in because of Good Faith. I've heard of a similar circumstance where an officer serving the warrant to the wrong address was shot by the occupant and the occupant wasn't charged with a crime because the cops got it wrong. I think in that case the warrant had the right street number but the cops made a mistake. Luckily no one died.
    – hszmv
    Dec 9, 2021 at 11:28
  • If I understand your answer correctly, you're saying this: "There's so many ways in which evidence can be illegal without the officer collecting the evidence having done something easily persecutable, or persecutable at all. Thus, without the discouragement of making the evidence inadmissible, there wouldn't be much reason to not illegally collect evidence, since the officers very often can get away with it due to immunity and the fact that the offended parties have little recourse in contesting such offenses."
    – user110391
    Mar 1, 2022 at 2:41

A major problem with the "punish the wrong-doing officer" route is that it relies on action outside the power of the courts. When a judge is faced with illegally obtained evidence, they have to deal with the case before them, that judge has no power to fine or jail the wrong-doing officer, that would have to be taken up by a prosecutor. The judge could refer the case to a prosecutor but there's no guarantee that any action would be taken. The prosecutor could just say "I've got better things to do, Officer Smith got a dirtbag off the street." and the judge would have no power to compel a different result.


They didn’t

At least in jurisdictions outside the .

In , , , and others, illegally obtained evidence is admissible. In most jurisdictions this is at the discretion of the judge based on whether the probitive value of the evidence outweighs the public interest in having the police obey the law.

In all of these jurisdictions, including the United States, police officers and forces can and do face criminal and civil sanctions when they break the law. However, you need to bear in mind that there are degrees of illegality from technical irregularities in a warrant through to beating a suspect for a confession.

The exclusionary rule is, as far as I know, unique to the United States and is a result of its particular history and circumstances.

  • In other common-law countries, is it possible for citizens to initiate criminal actions against government officials without requiring the cooperation of prosecuting attorneys? In the US that would generally not be available as a remedy, so in the absence of the Exclusionary Rule people whose rights were violated by police would often be left with no remedy whatsoever. On the other hand, I don't think the ER does a good job in situations where actions may be unreasonable but aren't patently unreasonable. Questions of "reasonableness" generally involve issues of fact...
    – supercat
    Jun 3, 2022 at 20:16
  • ...and should thus be among those a defendant should be allowed to have a jury consider. If the defendant claims a cop was lying about his motives for a search, a jury should be instructed to judge the cop's credibility, and only consider evidence from the search if they think the cop was telling the truth.
    – supercat
    Jun 3, 2022 at 20:19

In the U.S., tort and contract law generally eschew punitive measures – but not always.

However, criminal procedure routinely has punitive measures – for example those laid out in respective states' rules of professional conduct, particularly those rules directed at the special responsibilities of prosecutors.

Also, to hopefully help clarify the pros and cons between the two jurisprudential approaches presented, I would mention: if, in certain cases, the exclusionary rule leads to "good evidence being thrown out" – how much more would the prospect of "strong and fear-inducing punitive action" lead to a chilling effect that would, in effect, cause perhaps at least as much good evidence to be thrown out.

Also, to address SoronelHaetir's contention: Miranda v. Arizona (1966) showed that a court can invent for itself the authority to simply throw out an entire case based on even possibly tainted evidence. Thus, it would hardly strain credulity for a court to find its own discretion to hold in contempt those whose evidence arises by illegality.

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