Apparently, the legal understanding is that the Fourth Amendment doesn't guarantee some right that illegally obtained evidence can't be used against you (it merely guarantees that those obtaining the evidence illegally will be punished).

The reason why evidence obtained illegally is generally suppressed is to act as a deterrent to the Government. Even if individual officers were willing to risk their own punishment for illegal search or seizure (say, maybe they believe they are acting for the greater good), the evidence will generally be suppressed so that there is no rational gain from these illegal actions.

However, if the officers who obtained the evidence illegally were acting under good faith, then there is no deterrence obtained from suppressing the evidence they obtained. They did not act to illegally obtain evidence, in a way that they might be deterred from doing again if the evidence is suppressed - they thought they were collecting the evidence legally so they would do this again. So, in this case, there is no point in suppressing the evidence - no one is harmed by it being admitted (because, again, the Fourth Amendment doesn't promise you that illegally obtained evidence would not be used against you, it just promises that the Government will do all it can to avoid illegal search and seizure).

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plagiarist an hour ago | parent [-]

That interpretation is insane to me. If all it takes is, "haha, oops," to use evidence gained from an unconstitutional search, people do not actually have Fourth Amendment rights.

I guess I shouldn't be surprised, knowing that civil asset forfeiture is a thing.

	▲	qingcharles 3 minutes ago \| parent [-]
		This is mostly true. You have to remember that evidence exclusion for a constitutional violation is a modern thing, and it is what's known as "judge made," e.g. it wasn't made by legislature, it was invented by the courts. (Miranda warnings are the same -- I remember one time-travel book I was reading where the guy went back to 19th century New York and was complaining about the police beating him and not reading him his rights) So sometimes it can be kinda hand-wavy and bullshit, especially using the "good faith" exception which has been very over-used in the last decade or so, especially because of new technologies, which gives a get-out clause to the police unless the exact fact pattern of their "search" exactly matched some previous case that was solidified in appellate case law in their state or federal district, or by SCOTUS.