Your “rights,” otherwise known as the Miranda warnings, are a list of statements that law enforcement must recite to you before they can conduct a custodial interrogation. The Miranda warnings exist to protect your Fifth Amendment right against self-incrimination. If you understand these rights before you talk to the police, the legal theory goes, anything you say after that will be voluntary. While the exact wording differs between jurisdictions, the warnings are essentially as follows: You have the right to remain silent. You have the right to have an attorney present. If you can't afford an attorney, you will be provided one by the government. Anything you say can be used against you in court.
Every state requires police to give the warnings in some form after taking a suspect into custody. The goal behind the requirement is to protect the truthfulness of the evidence that will be later used in court. If a person feels pressured or intimidated into talking, it is assumed that they are less likely to tell the truth and more likely to tell the police what they want to hear. Verdicts based on coerced confessions erode the efficacy of the criminal justice system, and the Miranda warnings are intended to protect suspects from their own tendency to succumb to intimidation.
So, do the police have to read you your rights? The question hinges on whether you are in custody or not. The rule of thumb in determining the custody question is whether or not you feel free to leave. In most cases, the answer is pretty easy — if you've been arrested, then you are in custody and law enforcement must give you the Miranda warnings. There are some situations, however, that aren't so simple. For example, what if the police have stopped you on the street but haven't officially arrested you yet? Or, what if you have consented to the police entering your home for a chat? You may not be in handcuffs or at the police station, but you still may be in custody.
Of course, most people don't feel free to leave when they're talking to the police, but in the event that you did say something incriminating before the police gave you the Miranda warnings, a good attorney can help you determine whether you were in custody and whether a judge should disallow your statement to be entered as evidence against you.