To enforce the law and defend the interests of the United States according to the law; to ensure public safety against threats foreign and domestic; to provide federal leadership in preventing and controlling crime; to seek just punishment for those guilty of unlawful behavior; and to ensure fair and impartial administration of justice for all Americans.
The Department of Justice is pleased to provide the public with a variety of resources - from publications, reports, and frequently requested forms to case highlights, legal briefs, opinions and judicial orders. Explore here.
Investigate the agencies here. There are too many to list.
Don't forget to check out the archives!