Taking by law enforcement or other government agent of contraband, evidence of a crime, or even a person (via arrest) into custody.

Sensible, rational, and justifiable.

What would lead a person to believe that something connected with a crime is on the premises or person to be searched.

The sum total of factors leading a reasonable person to a course of action.

Emergency situations; they do not require a warrant.

Establishes that the courts cannot accept evidence obtained by unreasonable searches and seizures.

Dictates that a search conducted with a warrant must be limited to the specific items named in the warrant

Court-approved stipulation that an arrest or search warrant may be carried out at night.

Search warrant that contains a special provision permitting officers to execute the warrant without first announcing themselves.

Warrant based on prior knowledge or an affidavit showing probable cause that at some future time certain evidence of a crime will be located at a specified place.

Detaining, questioning, and possible frisking of an individual based on an officer's reasonable suspicion of that individual's involvement in criminal activity.

Establishes that evidence obtained as a result of an earlier illegality must be excluded from trial.

Establishes that illegally obtained evidence may be admissible if the police were truly not aware that they were violating the suspect's Fourth Amendment rights.

Requires that searchers consider the probable size and shape of evidence they seek.