Legal Definitions - spillover theory

The spillover theory is a principle in criminal law that states that a defendant can only be granted a separate trial if they can prove that being tried with a co-defendant would unfairly prejudice their case. This can happen when evidence that is admissible against one defendant is also used against the other defendant, even if it is not relevant to their case.

For example, if two people are accused of robbing a bank together, and one of them made a confession that implicates both of them, the confession could unfairly influence the jury's decision against the other defendant. In this case, the defendant could argue for a separate trial to avoid being unfairly prejudiced by the confession.

The spillover theory is based on the idea that a jury's unfavorable impression of one defendant could influence their view of the other defendant, even if the evidence is not relevant to their case. The goal is to ensure that each defendant receives a fair and impartial trial, without being unfairly influenced by evidence that is not relevant to their case.