"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing theplace to be searched, and the persons or things to be seized."
In criminal procedure, we've spent the bulk of the semester so far discussing the Fourth Amendment with respect to searches and seizures. This is a condensed and abridged version of some of what we've covered.
In order for the police to get a search warrant, the search, by definition, must be: 1. based on probable cause, 2. granted by a magistrate, 3. particularly descriptive, and 4. unreasonable.
If the police do a search without a warrant, that search must be subjectively reasonable to the people. Justice Scalia once noted that it's very interesting how what is reasonable to the public is always what is "reasonable" to the majority of the court.
When it comes to the conversations, there is a two prong test.
The first prong is whether the individual whose conversation is being listened in on by the police (local police are included through the 14th amendment incorporation of the first 8 amendments of the Bill of Rights) or other government entities enjoys a subjective "expectation of privacy."
The second prong is whether that expectation of privacy is objectively considered by the people to be "reasonable."
In other words, in the location where the person was, could/should he believe that his conversation was going to be private? It's not unreasonable to believe that a person's conversation would be reasonably considered to be private in his house. The same holds true in a telephone booth, if the door is closed, where you have done everything reasonably possible to shut the rest of the world out of your conversation (lip reading is possible, but not necessarily considered when detemrining whether the expectation is "reasonable"). However, a public park is never considered private, regardless of the circumstances, creating a bright line rule that is easy to understand.
Searches onto property may or may not be unreasonable, depending on the circumstances. If you've taken reasonable steps to shield your property from the outside, then you have a reasonable expectation of privacy up to that point. However, this is not absolute. If, for example, aircraft are allowed to fly low enough over your property to see into your yard, then it is not an unreasonable search for the government entity to fly a plane over your property to search (for example pot growing behind a 10 foot high fence). On larger pieces of property, your expectation of privacy does not extend all the way out to your fence. The police can enter your property and search up to the part of the property referred to as the "curtilage." This is the area immediately surrounding your house that would typically be treated more like the "home" area of a larger property; perhaps there's an interior fence, or something else that sends a signal to the rest of the populace that you consider this area more closely tied to your home. Police can search the property outside the curtilage without violating your 4th amendment rights, though you may have a 1983 action (civil rights violation) against the police for trespass to land.
Searches of persons and personal property. Typically, the police need a search warrant unless the search is subject to an exception. When the police have a warrant to arrest an individual, they can arrest the individual and then search him and the area immediately around him (the "grab area") where he might be able to find weapons that would cause the arresting agent harm. It's unclear how far this "grab area" extends, but it does seem to extend to rooms immediately adjacent to the room in which the suspect is arrested, including in closets and drawers. This is true even if the individual is handcuffed; the concept being that all suspects are blessed with the escapability of Houdini and the strength of Hercules. This same concept is what allows police to search a car after a suspect has vacated the car at the officer's direction and been secured. This is known as a Belton search, from New York v. Belton, the Supreme Court decision that allowed the searches. These searches are limited in scope, though, to the area immediately in the "grab area" of the suspect - which would be the cab, not the trunk.
Protective patdowns - the police, when they've stopped a suspect, may, do a brief protective patdown of the suspect to ensure the suspect is not carrying any weapons. We allow this as a general exception to the 4th amendment prohibition against unreasonable searches because we want to allow some protection for the police. During this time, they can pat down the individual for weapons, and may confiscate only items that are readily identifiable as contraband (for example a baggie that feels like it's holding pot is acceptable, but a TicTac box that, after you take it out of the suspect's pocket and open it to look inside contains heroin is not). If the person is being arrested, the Police may do a search incident to arrest, which would incorporate a more expansive search, such as the Belton search and home searches above.
I've not even gotten halfway through my notes and this is getting pretty long, so I'll save the rest of the description for some later time, if at all. For now, we'll look at the remedy.
The remedy for a search that is determined to be unreasonable is that the evidence gleaned from that search is inadmissible, as is any evidence discovered as a result of the illegal search (for example, an ill-gotten confession would be inadmissible, and if the confession stated where the murder weapon is, that weapon is inadmissible UNLESS the police can prove that said weapon WOULD HAVE BEEN FOUND within a short time of the actual discovery due to the confession - fruit from the poison tree doctrine).
Does the remedy of exclusion make any sense, really? By definition, the suppression benefits criminals (if the person is not guilty there is no evidence to suppress), which seems contrary to our concepts of justice. Do we not trust the police to have their own remedies in place for when one of theirs violates the fourth amendment, to ensure that they don't continue to do so? Should we allow the evidence in the case and then punish the officer who got it illegally in an unrelated hearing? Is the exclusion of evidence gotten through violation of the Fourth Amendment a good thing or a bad thing?