In the 1896 case of Allen v. United States, the U.S Supreme Court upheld a lower court's decision to admit evidence obtained through an unauthorized search and seizure. The defendant, William Allen, was convicted for receiving stolen property from a post office robbery after police found the items in his home during an illegal search. On appeal, he argued that this evidence should have been excluded due to its unlawful acquisition. However, the Supreme Court ruled against him stating that while it did not condone such actions by law enforcement officials; there were no constitutional or statutory provisions at that time which required illegally seized evidence to be excluded from trial proceedings. This ruling remained until 1914 when it was overturned by Weeks v United States which established what is now known as "the exclusionary rule".

In the dissenting opinion for Allen v. United States, Justice Harlan argued that the court majority had erred in its interpretation of reasonable doubt and burden of proof principles. He contended that it was inappropriate to instruct jurors they could convict based on a moral certainty rather than an absolute one, as this undermined the defendant's right to be presumed innocent until proven guilty beyond all reasonable doubt. Furthermore, he criticized the majority’s decision to allow evidence from unrelated crimes into consideration during trial proceedings. According to him, such practices were not only unfair but also potentially prejudicial against defendants who might have been involved in past criminal activities but were innocent of current charges being tried before them. In essence, Justice Harlan believed that these deviations from established legal norms threatened fundamental rights and protections accorded by law.