In the case of Greer v. United States (1917), the U.S Supreme Court ruled that a defendant's constitutional rights were not violated when he was tried and convicted based on evidence obtained through wiretapping, even if it was done without his knowledge or consent. The court held that such evidence is admissible in federal courts as long as it is relevant and material to the case at hand. This decision established an important precedent regarding privacy rights and law enforcement practices in criminal investigations, essentially allowing for warrantless surveillance by government authorities under certain circumstances.

In the dissenting opinion for Greer v. United States, Justice Holmes argued that the defendant's conviction should be overturned due to a lack of evidence supporting his guilt beyond reasonable doubt. He contended that there was insufficient proof to demonstrate that the defendant had knowingly and willfully misstated facts in violation of federal law. According to Holmes, it was possible that the defendant may have been mistaken or misunderstood certain details rather than deliberately lying about them. Therefore, he believed it was unjust to convict him based on such shaky grounds without more concrete evidence confirming his intent to deceive or defraud.