What must a prosecutor ensure when bringing charges against a defendant?

When a prosecutor brings charges against a defendant, it is crucial that there is probable cause to support those charges. Probable cause refers to a reasonable belief, based on facts, that a crime has been committed and that the defendant committed it. This standard helps to protect individuals' rights and prevents wrongful prosecutions, ensuring that only those against whom there is a sufficient legal basis are charged. Upholding this standard maintains the integrity of the judicial system and protects against arbitrary or unjust legal actions.

The other options do not accurately reflect the responsibilities of a prosecutor. Popular public opinion does not set a legal standard for charging decisions. Confidentiality is important in the legal process, but it primarily pertains to the handling of sensitive information and does not directly relate to the necessity of probable cause. Lastly, bringing charges hastily without evidence undermines the justice system and contradicts the ethical obligations of a prosecutor. Thus, the requirement for probable cause is foundational in ensuring justice is served properly.