If letters and private documents can thus be seized and held and used in evidence
against a citizen accused of an offense, the protection of the Fourth Amendment declaring his right to be secure
against such searches and seizures is of no value, and, so far as those thus placed are concerned, might as well be stricken from the Constitution... The tendency of those who execute the criminal laws of the country to obtain conviction by means of unlawful seizures and
enforced confessions, the latter often obtained after subjecting accused persons to unwarranted
practices destructive of rights secured by the Federal Constitution, should find no sanction in the judgments of the courts which are charged at all times with the support of the Constitution and to which people of all conditions have a right to appeal for the maintenance of
such fundamental rights.