In 1997, the United States Congress embarked upon an initiative to establish a document exchange standard for the transformation, creation, and exchange of legislative documents in XML format. XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. The initiative also included an effort to customize XML editors for the creation of bills and resolutions in the House and Senate. The initiative is rooted in a 1996 directive from the House Committee on Rules and Administration and the Senate Committee on Rules and Administration to the Clerk of the House and the Secretary of the Senate, respectively, to work together to establish common data standards for the exchange of legislative information (2 U.S.C. 181).
In 2000, the Clerk of the House of Representatives presented the SGML/XML Feasibility Study Final Report to the House Committee on Rules and Administration, and in 2001, the House Office of Legislative Counsel began to use an XML editor to draft legislation. The proliferation of Congressional XML continued in the early 2000s with House votes in 2003, House and Senate bills in 2004, and Senate Votes in 2009.
The XML generated since 2001 can be characterized as “First Generation”— meaning the markup primarily expresses the visual characteristics of a document. The First Generation is colloquially referred to as “Bill-DTD” XML. In 2013, the House Office of the Law Revision Counsel launched Congressional XML into its “Second Generation” with the release the United States Code in XML format using the United States Legislative Markup (USLM) schema. The USLM schema, which is interoperable with the LegalDocML international standard, not only describes the presentation of a document, it also expresses the structure of a document or how it is organized and the semantics of a document or what it means. Following the release of the United States Code in USLM XML, the House Rules Committee made multiple editions of the House Rules and Manual available in USLM XML. In 2016, a project was initiated through the Bulk Data Task Force to convert a subset of Enrolled Bills, Public Laws, and the Statutes at Large into USLM XML. The project was completed in 2018.