look is the reasoning provided by Supreme Court in MIRANDA v. ARIZONA, 384 U.S. 436 (1966)
http://caselaw.lp.findlaw.com/cgi-bin/getcase.pl?court=us&vol=384&invol=436
Among other things, the Court explained:
"A recurrent argument made in these cases is that society's need for interrogation outweighs the privilege. This argument is not unfamiliar to this Court. See, e. g., Chambers v. Florida, 309 U.S. 227, 240 -241 (1940). The whole thrust of our foregoing discussion demonstrates that the Constitution has prescribed the rights of the individual when confronted with the power of government when it provided in the Fifth Amendment that an individual cannot be compelled to be a witness against himself. That right cannot be abridged. As Mr. Justice Brandeis once observed:
"Decency, security and liberty alike demand that government officials shall be subjected to the same rules of conduct that are commands to the citizen. In a government of laws, existence of the government will be imperilled if it fails to observe the law scrupulously. Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example. Crime is contagious. If the Government becomes a lawbreaker, it breeds contempt for law; it invites every man to become a law unto himself; it invites anarchy. To declare that in the administration of the criminal law the end justifies the means . . . would bring terrible retribution. Against that pernicious doctrine this Court should resolutely set its face." Olmstead v. United States, 277 U.S. 438, 485 (1928) (dissenting opinion).
"In this connection, one of our country's distinguished jurists has pointed out: "The quality of a nation's civilization can be largely measured by the methods it uses in the enforcement of its criminal law." If the individual desires to exercise his privilege, he has the right to do so. This is not for the authorities to decide. An attorney may advise his client not to talk to police until he has had an opportunity to investigate the case, or he may wish to be present with his client during any police questioning. In doing so an attorney is merely exercising the good professional judgment he has been taught. This is not cause for considering the attorney a menace to law enforcement. He is merely carrying out what he is sworn to do under his oath - to protect to the extent of his ability the rights of his client. In fulfilling this responsibility the attorney plays a vital role in the administration of criminal justice under our Constitution.
"In announcing these principles, we are not unmindful of the burdens which law enforcement officials must bear, often under trying circumstances. We also fully recognize the obligation of all citizens to aid in enforcing the criminal laws. This Court, while protecting individual rights, has always given ample latitude to law enforcement agencies in the legitimate exercise of their duties. The limits we have placed on the interrogation process should not constitute an undue interference with a proper system of law enforcement. As we have noted, our decision does not in any way preclude police from carrying out their traditional investigatory functions. Although confessions may play an important role in some convictions, the cases before us present graphic examples of the overstatement of the "need" for confessions. In each case authorities conducted interrogations ranging up to five days in duration despite the presence, through standard investigating practices, of considerable evidence against each defendant. Further examples are chronicled in our prior cases. See, e. g., Haynes v. Washington, 373 U.S. 503, 518 -519 (1963); Rogers v. Richmond, 365 U.S. 534, 541 (1961); Malinski v. New York, 324 U.S. 401, 402 (1945).
= new reply since forum marked as read
tag is your friend in these posts. Or, provide sufficient context for us DU pedants. 
