4A protects the person, not the place. If you don't have an expectation of privacy in a thing, your rights can't be violated.
He has a subjective expectation of privacy, but objectively, does society wish to protect that expectation? Not on these facts, says the court: there'd have to be some indicia of your interests other than just your say-so.
Conflict of 5A and 4A rights! 5A wins: the statements are available for impeachment, but not in the case in chief.
So this was before 4A applied to the states; it wasn't till later (Mapp) that 4A got incorporated.
This is the holding that says federal officials can't violate 4A: evidence collected illegally by them can't be admitted.
Notice that this "motion to get property returned" still exists (Rule 41).
Justice Holmes: no, no, no. This is a 1.5-page decision. So we're seeing the start of the poisonous tree: not only can you not use improperly obtained evidence itself, but you also can't use the knowledge you gained from that.
Now 4 more officers (total of 7) show up. They knock, and then break in. They wave a piece of paper at her, she stuffs it down her shirt. They reach in and get it back. They ransack the house: no bomber, but they do find "obscene materials." They arrest her and charge her.
First and foremost, this is an obscenity case. She's appealing on 1A grounds, not 4A. But the majority is mad about these facts: we can't delegate these matters to the states, because look what you get. Exclusionary rule is incorporated via 14A.
In the end, though, basically this is the fruit of the poisonous tree doctrine. Justice Brennan actually uses the phrase in the opinion. And note that we're not just talking about the collection of physical evidence: any illegally obtained evidence taints everything that's derived from it.
And thus we begin the project of carving out exceptions; you can get to the same evidence via other means, and that would un-taint it.