.... and you are aware of this right thanks to a challenge to the State of Arizona's Gestapo-like police tactics by dedicated attorneys for 4 criminal defendants, among them Ernesto Miranda, whose famous name we all know.
In 1963, Mr. Miranda was arrested by Phoenix police and taken into custody, where he was interrogated and confessed to a crime, without having been told that he could refuse to answer questions or have an attorney. The confession was used at trial and he was convicted, and sentenced to 20-30 years imprisonment.
His dedicated attorneys pursued appeals through the Arizona and federal court systems, all the way to the U.S. Supreme Court in what would, these days, be a record-short time. In 1965, the U.S. Supreme Court held that the confession was inadmissible because of the inherently coercive nature of custodial interrogation, and overturned his conviction. [see footnote 1]
The Court went further, though, and held that without a requirement to provide defendants with a warning about their rights, the U.S. Constitution's Fifth and Sixth Amendment protections (right against self-incrimination and right to have a lawyer) would be rendered essentially useless.
So, thanks to Arizona and the attorneys for Mr. Miranda, we now have the ubiquitous "Miranda Warnings" recited on every cop show on television, approximately 18,642 times per week! Yay, Arizona!
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footnotes (because I'm a lawyer and lawyers love footnotes):
1. Although Mr. Miranda's initial conviction was reversed, he was retried and convicted again in 1967, even without the use of the illegally obtained confession. He was again sentenced to a 20-30 year term of imprisonment. However, he was paroled in 1972. (This was before Arizona adopted some of the most stringent sentencing laws in the nation, and virtually eliminated early release credits.) According to Wikipedia, Mr. Miranda made a living for a while by autographing police officers' "Miranda warning cards," and was later stabbed to death during a bar fight on January 31, 1976.