Which case established the 'fruit of the poisonous tree' doctrine as a critique of tainted evidence?

• A. Mapp v. Ohio
• B. Barnette
• C. Wong Sun v. United States
• D. Schenck v. United States

Answer: (C)

The main idea is the fruit of the poisonous tree doctrine, which says that evidence obtained through an unconstitutional search or seizure is generally not admissible, and derivatives of that tainted evidence can be excluded too to deter police misconduct.

Wong Sun v. United States (1963) is the case that gave the doctrine its famous articulation. The Court held that when police action is illegal, not only the directly seized items are suspect, but evidence that flows from that illegality—derivative or “fruit”—is typically excluded as well. The decision emphasizes limiting the use of tainted leads in criminal prosecutions and set up the framework for how derivative evidence should be treated, including the idea that some connections to the illegality can be attenuated or have independent sources, which affects whether the taint applies.

Mapp v. Ohio extended the exclusionary rule to the states but did not establish the doctrine itself; Barnette and Schenck are about First Amendment speech issues, not tainted evidence.