§ 400 [Preliminary Fact Defined]

Before a judge allows certain evidence or testimony in court, they may need to answer a basic question first. That question hinges on what this rule calls a "preliminary fact."

A preliminary fact is something that must be true (or not true) before evidence can be used in a case. For example, before someone can testify as a witness, the judge may need to confirm that the person is qualified to do so. The same idea applies to privileges, like the right to keep a conversation between a lawyer and client private.

Think of it as a gatekeeper step. The judge checks the preliminary fact first, and that check decides whether the evidence or testimony gets in or stays out.