Criminal Law Professor Sandra Guerra Thompson with the University of Houston says prosecutors used the silence of the suspect to convict him.
"What you have here, though, is the court talking about a person's silence. And so we're not actually talking about a confession by words where a person affirmatively says 'I did it' but rather the refusal to say something, or you know, the suggestion that if, you know, 'if this had been true you would have said it, and you didn't'."
The Fifth Amendment protects against forced self-incrimination, and so-called "Miranda Rights" were introduced to ensure that police let suspects know of that right. But prosecutors argued that since the suspect answered some questions and he wasn't under arrest or invoking his right to silence, his silence on incriminating questions doesn't get constitutional protection.
"So basically, you know, if a person is silent in the face of police questioning — and before Miranda — then under this decision the government can use that."
Professor Thompson says says lawyers will have to go about things differently.
"We might see lawyers arguing more for the exclusion of certain silence or certain statements based on more evidence rules and about how reliable this kind of evidence may be."
The 5-4 ruling comes in the case of Genovevo Salinas, convicted of a 1992 Houston murder.