Deliberative process privilege is a legal rule that says people involved in making decisions cannot have to tell anyone else what they were thinking. It is like a privacy law that applies to discussions by government decision makers when they are making decisions. The idea is to keep the decision making process private so that the decision makers can talk freely and openly without worrying about what other people will think. This helps make sure that decisions get made without any outside people trying to influence it. It is like a secret between the people in the discussion, and nobody else can find out what was discussed.