The two principal statutes enacted against perjury, Sections 1623 and 1621 of the United States Code, are compared and contrasted with regard to several elements: oath before a competent tribunal, officer, or person; oath authorized by United States law; intent; States subscribes to or makes or uses false information; materiality; falsity, and knowledge of falsity. Common defenses against perjury charges include entrapment, good faith, and collateral estoppel, while other issues involved in the defense include recantation, inconsistent declarations, immunity, and role of counsel. The elements surrounding false statements include the statement itself, falsity, knowledge, intent, materiality, and matters within the jurisdiction of any department or agency. In addition to the defenses already mentioned, the only other common defense is that of reliance upon the advice of counsel or another expert. The defense against charges of false statements must also consider statute of limitations, overlap with other statutory violations, venue, and multiplicity or duplicity. The discussion of obstruction of justice focuses on an analysis of the relationship of U.S. Code Section 1503 to Sections 1512 and 1513 and their unique and common elements. Some of the issues examined include endeavor, use of threats or force, knowledge, and influence or intimidation. 368 notes