Whether the exclusionary rule includes an inevitable-discovery exception permitting admission of evidence derived from a constitutional violation when lawful means would ultimately have discovered it.
Holding
Yes. Evidence is admissible if the prosecution proves by a preponderance of the evidence that it ultimately or inevitably would have been discovered through lawful means.
Reasoning
The exclusionary rule generally bars both illegally obtained evidence and its derivative "fruit," but its purpose is not to make facts permanently unavailable to the prosecution. The independent-source doctrine permits use of evidence actually obtained through lawful, independent means; it prevents the government from benefiting from illegality while also preventing it from being placed in a worse position than it would have occupied without the violation.
The inevitable-discovery doctrine follows the same principle. Although the evidence here was actually located because of Williams' unlawfully elicited statements, the government would be unfairly placed in a worse position if evidence that lawful police activity would have uncovered anyway were suppressed. If lawful discovery was inevitable, the unlawful conduct did not give the prosecution an evidentiary advantage at trial.
The Court set the burden at a preponderance of the evidence, the ordinary standard governing admissibility determinations at suppression hearings. Inevitable discovery turns on concrete historical facts about an ongoing investigation that can be tested through evidence and cross-examination; it does not require the heightened clear-and-convincing standard urged by Williams.