Positive law codification - U.S. Code

The United States Code (U.S.C.) is a codification of the federal laws in force. Some of the titles (e.g., title 17) have been enacted as positive law by Congress. When Congress amends these, it amends the U.S.C. directly. Other titles (e.g., title 42) are compiled from individual statutes and have not been enacted as a whole. When Congress amends these, it amends the original public law.

The U.S.C. titles that are not positive law are prima facie evidence of the law, but the official real-deal law is the original enactment in United States Statutes at Large. That's why you sometimes see citations to § 202 of the Social Security Act, rather than 42 U.S.C. § 402, where it's codified. Congress currently is working on enacting two more titles as positive law: H.R. 1107 (title 41, Public Contracts) and has H.R. 3237 (title 51, national and commercial space programs) have both passed the House and are pending in the Senate. The Law Revision Counsel -- the official in charge of codification -- explains why this project is important: Peter Lefevre, Positive law codification will modernize U.S. Code, The Hill's Congress Blog, Sept. 28, 2010. For more (if you think the inner workings of codification are as interesting as I do), see my short article: Mary Whisner, The United States Code, Prima Facie Evidence, and Positive Law, 101 Law Libr. J. 545-56 (2009), available at https://ssrn.com/abstract=1517999.