Which principle challenges the legality of evidence obtained without a warrant?

The principle that challenges the legality of evidence obtained without a warrant is the exclusionary rule. This rule is a judicial doctrine that prohibits the use of evidence gathered in violation of the Fourth Amendment, which protects against unreasonable searches and seizures. When law enforcement conducts a search or seizure without a valid warrant or without exceptions to the warrant requirement, any evidence obtained as a result of that unlawful action may be deemed inadmissible in court due to the exclusionary rule. This principle is crucial for upholding the rights of individuals and ensuring that law enforcement abides by constitutional standards when gathering evidence.

The good faith exception, while related to the exclusionary rule, allows for evidence to be used in court even if the warrant was technically flawed, provided that law enforcement officers acted under the belief that they were following the law. Probable cause is the standard required for obtaining a warrant and does not directly address the legality of evidence once it has been collected. Double jeopardy refers to the legal concept that prevents a person from being tried twice for the same offense, which is unrelated to the admissibility of evidence.