In the excellent true crime book, "Homicide: A Year on the Killing Streets", David Simon (future creator of The Wire), talks about the Miranda warning in the co

In the excellent true crime book, "Homicide: A Year on the Killing Streets", David Simon (future creator of The Wire), talks about the Miranda warning in the context of interrogations. When originally introduced, law enforcement bemoaned that this would hamstring their ability to gain confessions from suspects, because any sensible criminal would simply ask for a lawyer. He then goes on to explain that wily police detectives, instead, were able to use Miranda as a tool - "this is something we have to get out of the way so we can get you home" and "look, you can get a lawyer, but then we can't figure this out right here". He points out that lying to suspects is both a tool and a risk - if you tell a suspect that there was blood found on his shoes, and the suspect knows that he wasn't wearing those shoes during the crime, he knows you have nothing. I highlight this because it's fine and good to ban lying to suspects, but not all lies are strictly untrue, and it's possible to use partially true statements to one's benefit in an interrogation. Simon points out that interrogations, by their very nature, are coercive, and if we really want to protect the rights of suspects, mandating an attorney present at an interview is the only way to ensure that.