My question involves criminal law for the state of: USA
If a person pleads to an indictment and that indictment is later found to have had some invalid charges on it, does the ENTIRE indictment become invalid or just the part that includes the invalid charges leaving the rest to have legal effect? Can it be retro-actively made valid? Does the entire plea become invalid because the person was not aware of the the lawful charges made against him and if he had known might have pleaded differently?
I appreciate any case law that the members of this board might be able to offer.

