In a 5-4 decision the Supreme Court ruled today that a potential defendant's silence can be used against him if he is being interviewed by police but is not arrested (and read his Miranda rights) and has not verbally invoked the protection of the Fifth Amendment.

Tim Lynch at the Cato Institute explains that the Salinas v. Texas case was intended to be about whether prosecutors during a trial could cast aspersions on a defendant's silence during questioning that took place prior to arrest — prior to the defendent being told he had the right to remain silent. Instead, the Supreme Court determined that they wouldn't need to rule on the matter because the defendant had never invoked the Fifth Amendment's protection. This decision means that it's the responsibility of the individual to know about the protections offered by the Fifth Amendment even prior to arrest and to actually verbally invoke it:

The Court said Salinas simply remained silent and did not "formally" invoke any constitutional right, so prosecutors could offer commentary to the jury. What's most disturbing about the ruling is its discussion of "burdens." The plurality put the onus on the individual, not the government.