Final answer:
Probable cause is a legal standard for search, seizure, or arrest, which is determined by the 'totality of circumstances' test, as established in Illinois v. Gates. Informant information corroborated by police can establish probable cause, even if the information alone lacks veracity or a clear basis of knowledge.
Step-by-step explanation:
The inquiry pertains to the concept of probable cause within the realm of law enforcement and how it applies to validating law enforcement actions, such as obtaining a search warrant or making an arrest. Probable cause is a legal standard that officers must meet to conduct a search, seizure, or arrest. This standard is lower than what is required to secure a conviction at trial, which necessitates proof beyond a reasonable doubt. According to Illinois v. Gates, the "totality of circumstances" is used to determine if probable cause exists under the Fourth Amendment, which means that the veracity and basis of knowledge of an informant's information can be buttressed through police corroboration.
Moreover, certain situations do not require a search warrant such as when searching the passenger compartment of a car, or at border entries. Conversely, the exclusionary rule prevents unlawfully obtained evidence from being used in court, though there are exceptions to this rule such as the good faith exception and the inevitable discovery doctrine.