In the 1930 Supreme Court case Prussian v. United States, the court examined whether a U.S. citizen could be deported for criminal activities committed prior to their naturalization. The defendant, Mr. Prussian, was an immigrant from Russia who had become a naturalized U.S. citizen in 1914 but was later convicted of conspiracy to violate Prohibition laws and sentenced to two years imprisonment in 1922. The government sought his deportation under immigration law that allowed for removal of any alien who had been convicted of committing a crime involving moral turpitude within five years after entry into the country and sentenced to imprisonment for one year or more. Prussian argued that he should not be subject to deportation because he became a citizen before committing the crime and therefore wasn't an "alien" at time of conviction as defined by immigration law. However, the Supreme Court ruled against him stating that his citizenship did not protect him from deportation if it was obtained fraudulently or illegally - which they determined it was due to false statements made during his naturalization process about previous criminal activity.

In the dissenting opinion for Prussian v. United States, it was argued that the majority's decision to uphold a conviction based on circumstantial evidence was flawed. The dissenting justices believed that there were other plausible explanations for the defendant's actions and behavior which did not necessarily point towards guilt. They felt that in order to convict someone of a crime, especially one as serious as espionage, there must be clear and convincing proof beyond reasonable doubt - something they thought lacking in this case. Furthermore, they expressed concern over potential violations of due process rights given what they perceived as an overly broad interpretation of espionage laws by the prosecution and trial court judge during proceedings.