Basically, if you’re ever in any trouble with police (no, we don’t condone breaking laws) and want to keep your mouth shut, you will need to announce that you’re invoking your Fifth Amendment right instead of, you know, just keeping your mouth shut. ‘Petitioner’s Fifth Amendment claim fails because he did not expressly invoke the privilege against self-incrimination in response to the officer’s question,’ reads the opinion from Justice Samuel Alito, which Justice Kennedy and Chief Justice John Roberts backed. Justices Thomas and Scalia had a concurring opinion while the remaining four Supremes dissented. [emphasis added]
…nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law…