What does the poisonous tree doctrine establish?

• A. The poisonous tree doctrine; evidence obtained after illegal government action will be excluded
• B. Confessions obtained under coercion are admissible
• C. Evidence obtained from a valid warrant is always admissible
• D. The exclusionary rule applies only to felonies

Answer: (A)

The poisonous tree doctrine centers on the idea that when police obtain evidence through an illegal action, the initial tainted evidence is excluded, and anything later derived from that tainted evidence is also excluded. In other words, the illegal action contaminates the entire chain of evidence, so not only the direct result of the wrongdoing but also subsequent information discovered because of it cannot be used in court. This rule supports deterrence: if illegal tactics don’t lead to usable evidence, law enforcement has less incentive to violate rights. While there are exceptions—like independent source or attenuation where the link to the illegality is sufficiently weakened—the default position is that evidence obtained after illegal government action will be excluded. Confessions obtained under coercion are inadmissible, but that concern isn’t what the poisonous tree doctrine specifically addresses. Likewise, the fact that some evidence comes from a valid warrant doesn’t automatically save tainted evidence, and the exclusionary rule applies beyond felonies.