[whoknew1122]

The cited ruling answers your question

The court ruled that at the time, when the State Police opened the file, they had no reason to believe that a warrant was required. While the search was later ruled unconstitutional, no court had ruled it was unconstitutional *at the time of the search*. One of the cornerstones of American jurisprudence is that you cannot go back in time and overrule decisions based on contemporary jurisprudence.

From the opinion: 'the exception can also apply where officers “committed a constitutional violation” by acting without a warrant under circumstances that “they did not reasonably know, at the time, [were] unconstitutional.”'

If you're interested, the discussion of a good faith exemption (and why fruit of the poison tree doesn't apply here) begins at page 40 of the doc.

[krageon]

As someone not from the US the fact that "uwu we didn't know" is an adequate defense for the police to do something illegal is really weird. Is there some crucial context I'm missing?

[whoknew1122]

It dates back to the constitutional ban on "ex post facto" laws. Meaning, the government can't retroactively make something illegal. Which is a good thing, IMO.

So, for example, it's illegal at the federal level to manufacture machine guns (and I'm not going to get into a gun debate or nuances as to what defines a machine gun--it's just an example). But a machine gun is legal as long as it was manufactured before the ban went into place. Because the government can't say "hey, destroy that thing that was legal to manufacture, purchase, and own when it was manufactured."

This concept is extrapolated here to say "The cops didn't do anything illegal at the time. We have determined this is illegal behavior now, but we can't use that to overturn police decisions that were made when the behavior wasn't illegal. In the future, cops won't be able to do this."

[Izkata]

It wasn't illegal (unconstitutional) at the time they did it, which is different from not knowing. They would have had to see the future to know.

Also keep in mind "illegal" and "unconstitutional" are different levels - "illegal" deals with specific laws, "unconstitutional" deals with violating a person's rights. Laws can be declared unconstitutional and repealed.

[thinkingtoilet]

Just another way cops can be terrible at their job and get away with it. If only citizens could use the Chappelle defense, "I'm sorry officer, I didn't know I couldn't do that".

[whoknew1122]

Let's be clear. This guy had CSAM and was caught using digital forensics. The cops would've been able to secure the search warrant at the time had they been required to do so.

This isn't some innocent person who is spending time in prison because of a legal technicality.