It is difficult to argue that the 1966 decision by the United States Supreme Court in Miranda v. State of Arizona has harmed the public interest or not proven beneficial to society. 

Ernesto Miranda had been convicted of the charges of kidnapping and raping an 18-year-old woman on the basis of his written confession. That confession, however, had been produced following Miranda's interrogation by police officers who were able to exploit the accused's ignorance of his rights against self-incrimination under the fifth amendment to the U.S. Constitution, the relevant section of which reads as follows:

"No person shall be held to answer for a capital, or otherwise infamous crime . . . 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 . . ."

In addition the application of the Fifth Amendment to the Constitution, Miranda's conviction, the Supreme Court found, also ran afoul of the accused's rights under the Sixth Amendment, the operative section of which reads:

"In all criminal prosecutions, the accused shall enjoy the right . . . to have the assistance of counsel for his defense."

Because Miranda, as well as other defendants in unrelated cases, had not been specifically made aware of his rights under the Constitution by the police department, the Supreme Court, by a 5 to 4 majority, concluded that Miranda's constitutional rights had been violated. In his opinion in support of the majority decision in Miranda v. State of Arizona, which, as noted, actually involved multiple unrelated criminal cases each of which were characterized by convictions attained through improper methods, Chief Justice Earl Warren wrote:

"The constitutional issue we decide in each of these cases is the admissibility of statements obtained from a defendant questioned while in custody or otherwise deprived of his freedom of action in any significant way. In each, the defendant was questioned by police officers, detectives, or a prosecuting attorney in a room in which he was cut off from the outside world. In none of these cases was the defendant given a full and effective warning of his rights at the outset of the interrogation process. In all the cases, the questioning elicited oral admissions, and in three of them, signed statements as well which were admitted at their trials. They all thus share salient features -- incommunicado interrogation of individuals in a police-dominated atmosphere, resulting in self-incriminating statements without full warnings of constitutional rights."

The effect of the Court's decision, we know, is that criminal defendants, or suspects, must be made aware of their constitutional right against self-incrimination and their right to legal counsel during any police interrogation. The process of "Mirandizing" suspects, then involves the declaration by the arresting police officers and/or by prosecuting attorneys that the suspect sitting in the back of a patrol car or across from them in an interrogation room has the right to remain silent, and that any comments the suspect makes can be used against him or her in a subsequent criminal proceeding.The suspect is further informed that he or she has a right to have a lawyer present during questioning. 

So, the question becomes, did the Supreme Court's decision in Miranda v. State of Arizona have a deleterious impact on the criminal justice system that has threatened public safety? The answer is "no, it did not." Many members of the public believed at the time that the requirement on the part of law enforcement agencies that they inform suspects of their constitutional rights would benefit criminals at the expense of society. To the extent that pre-Miranda confessions had been useful in prosecuting criminals, it stood to reason, then the challenge for law enforcement post-Miranda had to be daunting, at the expense of public safety. That, however, has not been the case. While the challenge for law enforcement was made more difficult, it also eliminated some of the injustices inherent in the earlier system, as suspects could be coerced or otherwise tricked into admitting to crimes they may or may not have committed. 

Governments are powerful entities, and can bring resources to bear against indigent defendants that makes the justice system somewhat precarious. That is the beauty of the Bill of Rights: those ten amendments guarantee that the individual citizen enjoys some measure of protection against an overly intrusive government. More to the point, there has, in practice, been scant evidence that the requirement to inform suspects of their constitutional rights has imperiled public safety. Suspects are still convicted at a high rate, although it is equally true that prosecutors are loath to bring to trial defendants the evidence against whom is less than ironclad. Additionally, many criminal suspects are not very bright, and confess to arresting officers and to prosecutors without being interrogated. Juveniles, in particular, are known to be incapable of remaining silent, sometimes to their detriment, as they implicate themselves without prompting by police.

If one wanted, or needed to argue that Miranda v. State of Arizona has not benefited society, he or she could insist that criminals have been released into the public because of their knowledge of their rights. That is a very difficult argument to make, however, because it simply is rarely true. When it is true, it is usually because the prosecution's case rests primarily on circumstantial evidence. Cases that rest on solid, physical evidence, such as DNA or fingerprints, for example, are not threatened by the absence of a confession.