US constitutional law prohibits the introduction of evidence obtained illegally.
https://en.wikipedia.org/wiki/Exclusionary_rule ("Exclusionary rule")
There's no "retroactive" exception. The core point of this rule is to deter police from intentionally violating people's rights, under the expectation that what they find will, "retroactively", vindicate them. Won't work.
How would you know when it did? You can’t “retroactively” justify an arbitrary search under the exclusionary rule, but this doesn’t exclude evidence tangential to a legally-executed warrant during the execution of that warrant. For example, suppose someone is suspected of illegally possessing wildlife. A search warrant is issued on the residence. No wildlife is found, and in fact no wildlife was ever on the premises. If officers find large quantities of cocaine during the search, they aren’t precluded from making an arrest, because the warrant used to gain entry and conduct the search was legal.
https://en.wikipedia.org/wiki/Plain_view_doctrine
> In Arizona v. Hicks, police officers were in an apartment investigating a shooting and suspected that a record player in the apartment was stolen. The officers could not see the serial number, which was on the bottom of the record player, so they lifted the player and confirmed that its serial number matched that of one that had been reported stolen. However, the Supreme Court ruled that lifting the record player constituted an additional search (although a relatively nonintrusive one) because the serial number was not in plain view.
There were laws in Germany to prevent what Hitler did. It still happened.
None. The endless videos, from better-years-gone-by of people refusing to answer questions at the border then having drug dogs run all over their car to scratch it up was my first exposure to federal agents acting maliciously.
You might be able to argue harassment or malicious prosecution if it's just one part of an ongoing campaign but even that is going to be hard to argue if everything is within the bounds of the law.
See "three felonies a day" - if everyone will casually and unknowingly break some law daily, selective enforcement can be used maliciously.
Let's be real, it can be both. A legal, valid and justified search can be done in a manner calculated to inflict maximum pain. Raiding in the middle of the night instead of when they step out their door in the morning, ripping open walls when all they're really looking for is a laptop, flipping and trashing the place in a excessive manner, breaking things in the process, pointing guns at children, shooting the family retriever, etc. I don't know if they took this raid too far in any of these ways, but it wouldn't surprise me.