What does the phrase 'fruit of the poisonous tree' refer to?

The phrase 'fruit of the poisonous tree' refers to the legal principle that any evidence obtained through illegal means, such as an unlawful search or seizure, is tainted and therefore inadmissible in court. This doctrine is designed to deter law enforcement from engaging in unconstitutional practices. If the initial evidence or information was obtained in violation of the Fourth Amendment rights, any further evidence that is derived from that illegal action is considered 'fruit' that is also poisoned, hence inadmissible. This principle reinforces the integrity of the judicial process by ensuring that evidence is collected in a lawful manner.

In contrast, evidence obtained after a valid search warrant is typically admissible, as the warrant indicates that the search complied with legal standards. Voluntary statements made by suspects can be admissible, provided they were given without coercion. Judicial decisions, while impactful, do not fall under the same category of evidence admissibility related to unlawful searches or seizures.