The changes in criminal interrogation procedure established by the 1966 Supreme Court decision, generally known as Miranda v. Arizona ruling, have contributed to the formation of modern U.S. system of criminal interrogation and defined the main directions of its current development. Therefore it is interesting to analyze the historical significance of Miranda v. Arizona, with a view to determining its impact on the U.S. interrogation and police services. 
The adoption of Miranda v. Arizona  took place within the context of the growth in violent crimes that was characteristic of the 1960s. The confession procedure that was in place at that time was substantially amended by the Supreme Court's 1940s rulings , which were adopted in order to prevent unfounded convictions. The main effect of such decisions was to produce the so-called test of voluntariness that presented a rather undeveloped mechanism of establishing the exact will of the suspect in his/her conviction (Thomas).
The principal motivation behind the test of voluntariness was to ensure equal treatment of suspects from all racial and class backgrounds. However, actual results of its application were rather meager, as the myriad of factors listed in the criteria of the test of voluntariness was mostly unsystematic and generally ill-defined (Grano). This was especially important, as the police moved from traditional heavy-handed methods of interrogation to more subtle ones at the time, and the test of voluntariness requirements generally failed to account for them. 
Ernesto Miranda, the criminal suspect whose case became a foundation for the respective Supreme Court ruling, was apprehended on 13 March 1963 in Phoenix, Arizona, and was charged with rape and robbery for the crimes he committed in this city. Miranda was taken to a Phoenix police station, where, after the witnesses identified him as a culprit, he was interrogated by local police officers for two hours, without being informed of his right to have an attorney present (Samaha 270). Nonetheless, at that time the officers who arrested Miranda managed to produce a statement of confession from him, with the suspect confirming that his confession was given under no duress and “with full knowledge of my legal rights, understanding any statement I make may be used against me” (qtd. in Samaha 270).
Although one of the officers later claimed that he read this statement to Miranda before the latter signed it, subsequent court hearings established that this was not the case. At Miranda’s trial, the written conviction he gave to the police was considered as a part of inculpatory evidence in spite of defense’s objections, and the testimony of the officer according to which Miranda had given an oral confession before signing the statement was likewise received by the court. Eventually Miranda was sentenced to 20 to 30 years in prison on each count (i.e. kidnapping and rape), which were to be run concurrently (Samaha 270). Arizona’s Supreme Court later affirmed this sentence. 
The constitutional issue that was present in Miranda’s case concerns the potentiality for pressure on the suspect within the atmosphere of necessarily secret police interrogation. The police’s psychological pressure that cannot be excluded when dealing with such cases is surely an important factor in obtaining the suspect’s confession, and therefore the objectivity of interrogation might be compromised by it. The prevention of such situations requires  presence of the third party that may advise a defendant on the most beneficial course of action in weighing in confession and decrease the chances for psychological pressure on behalf of the police. That is why the defense counsel’s presence was considered by the Supreme Court to be the most secure guarantee against the breach of defendant’s rights. 
Thus the Supreme Court ruling on the case took into account the issues posed by the absence of the defense during Miranda’s interrogation. The Court ruled that “an individual held for interrogation must be clearly informed that he has a right to consult with a lawyer and to have a lawyer with him during interrogation under the system of protecting the privilege” of self-incrimination (U.S. Supreme Court). The failure to do so would compromise the results of interrogation and make it invalid to refer to them in court. Moreover, indigent suspects should have a right to receive a defense counsel appointed by the court if they lack funds to hire him/her themselves (U.S. Supreme Court). The presence of an attorney at the interrogation procedure was not deemed as running counter to law enforcement procedure.
The Court decided to apply the traditional FBI procedure of “advising any suspect or arrested person… that he is not required to make any statement, that any statement may be used against him in court, that the individual may obtain the services of an attorney of his own choice” to the cases considered by courts of justice (U.S. Supreme Court). 
The effects of Miranda v. Arizona ruling  are manifold; they have left deep imprint on the practices of the U.S. court and police system by establishing a clear model of conduct of law enforcement officers when dealing with issues of interrogation and conviction. The ‘Miranda rule’ effectively defines a mode of interaction between police operatives and suspects, preventing police abuse and providing for coherent rights statements for the detained suspects. 
In my opinion, the ‘Miranda rule’ has made it more difficult for the unscrupulous police to obtain ungrounded convictions from suspects and allowed for the establishment of clear-cut legal framework on interrogation that was generally lacking until that time. Both opponents and supporters of ‘Miranda rule’ agree that its implementation did not lead to either increase or decrease in numbers of suspects that refuse to co-operate with the police during the interrogation. Even though some more hard-line opponents of this Supreme Court decision, such as Professor Paul Cassell, claim that the repudiation of ‘Miranda rule’ would prevent the release of 3 to 4% of criminal suspects that may make use of the rule to act on defective waivers, in general the ‘Miranda rule’ is a necessary counterweight to a growing law enforcement agencies’ power. 
Grano, Joseph D. “Miranda v. Arizona and the Legal Mind: Formalism’s Triumph over Substance and Reason.” American Criminal Law Review 24.243 (1986-1987): 267-287. Print. 
Samaha, Joel. Criminal Procedure. 8th ed. Belmont, CA: Wadsworth Publishing, 2011. Print. 
Thomas, George C. “The End of the Road for Miranda v. Arizona? On the History and Future of Rules for Police Interrogation.” American Criminal Law Review 37.1 (2000): 1-39. Print. 
U.S. Supreme Court. Miranda v. Arizona. 384 US 436 (1966). Print. 
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