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Legislative Modernization: United States Law


I’ve done a lot of thinking about the original sources of U.S. federal law. And I’m fortunate to work with the people who draft, amend, organize, and analyze the law. Much of the law is published in fragments distributed across paper volumes and across various federal websites. Publication of the law is also distributed in time: publications that were up-to-date a year ago are still online, but not updated in-place. Depending on which federal website you look for the law, you may find a snapshot (often outdated) of the fragment of law that is maintained there.

Today I believe we are just a few steps from joining those fragments into an official, online, citeable -- and updated -- public framework of law.

This post will summarize the progress that has been made in modernizing the digital publication of law. Completing this effort requires solving three key problems of digitization (citations, version control and cloud deployment) and connecting three key sources of federal law (bills, U.S. Code, Statute Compilations). I plan to write separate posts to further explore each of those areas. The topic of regulations deserves its own treatment.

The nature of our federal system is that different organizations are responsible for each of the sources of federal law: bills, statutes and the United States Code are each managed by independent entities. So, much of the progress I will describe is due to the collaboration between some very dedicated people across many government organizations.

Some of what I discuss here can be found in earlier forms on this blog. This post is an attempt to update the information and identify the remaining challenges.

Modernizing the Digital Publication of Law

Citations as URL

An essential component of laws is the ability to cite a portion of law with some precision. Legislative citations typically cite a level in a hierarchical structure (Section 401(c) of Title 26 of the United States Code or 26 U.S.C. 401(c)). Digital citations refer to a URL. Modernization of law begins with creating a one-to-one relationship between the structure of a traditional citation and a URL: 26 U.S.C. 401(c) becomes /us/usc/t26/s401/c. (We can quibble in the comments about the differences between a URL and URI.)

In my view, the digital citation is the most important reason to translate legislative documents from paper into a digital format. The digital citation is embedded in the document itself as an 'identifier' in USLM, the official XML format for federal legislative and regulatory documents. It can also be used as a reference (or hyperlink) from another document. This makes a natural transition from the paper world of citations and references to the digital world of hyperlinks. In the Comparative Print project for the United States House, the digital citation allows us to automatically execute an amendment: amendments typically consist of a citation (where the change will be made), an action (e.g. a strike or insertion), and content (what is stricken or inserted). With a digital citation, we can retrieve the content to be amended from the database, make the change and set the changed provision as a new version -- or 'branch' -- of the document. There are lengthy and sometimes contentious discussions about how to structure law in digital form, and my guiding principle is the natural language citations that have been refined over centuries: if the citation exists in natural language, we should (generally) be able to make a digital reference to it.

Each of the three sources of federal law I describe below (bills, U.S. Code, Statute Compilations) is now published as downloadable files in United States Legislative Markup (USLM), a standardized XML format that includes digital citations for each portion of the text, or provision.

Version Control

“Just put laws into git” is a familiar refrain for anyone who has been working with digital law for a while. I gave a presentation at a Github conference about why solving the problem is both not that simple, but also not impossibly complex. In fact, my colleague Sela Mador-Haim has built an XML database, XCiteDB, that manages versions of every level of XML, and also tracks metadata about each level in a data-friendly format (JSON). This database is now being used by the House of Representatives to manage versions of the law as part of the Comparative Print tools. Version control is essential to be able to ask the question —— how would a bill written two years ago have changed the law as it existed at the time?

A major obstacle to version control is that intermediate versions of many documents are not stored. The sooner we start to save documents in a version-control database, the further back our record will go. That is why a second important step of modernization (after digital citations) is to manage documents in version control as soon as possible.

An alternative is to try to reconstruct the history of a document—something that is possible by tracking amendments to laws from their original enactment. However, that process is more involved and labor intensive than storing each document, as it is currently updated, in a version-control database.

Although, with XCiteDB, the technology now exists, there is currently no public site where federal law is being stored in a way that provisions can be retrieved using a point-in-time query.

Digital Publication and Cloud Deployment

Another important technical challenge is how laws are digitally published. We know that posting pdfs is not enough to modernize publication. After pdfs, the next evolutionary stage of online publication, ‘Bulk Data’, allowed technical users to download laws, process them, and sometimes republish them — as trailblazing sites like and Cornell’s LII have done. A more modern approach is to publish APIs, where documents, and information about the documents, can be downloaded selectively by technical users. GPO and the Library of Congress have provided very useful APIs to legislative data.

The next stage, however, is publication of the laws as a public resource: a searchable, dynamic online publication, where citations translate to URLs and URLs translate to citations. To do this requires solving the earlier two challenges (citations as URLs and updating laws with version control), as well as developing a modern cloud infrastructure and robust deployment processes for the law.

As mentioned earlier, it will also require careful coordination between the stewards of our laws, in various entities across the federal government. Below, I briefly describe each data source and its current state of digitization.

Modernizing the Sources of Federal Law: Bills, U.S. Code, Statute Compilations

Here, I discuss three sources of federal law that emanate from Congress: bills, the U.S. Code, and the Statute Compilations.


Federal bills originate in Congress. These have been published in a structured digital format for years and are now available from the Government Publishing Office in United States Legislative Markup (USLM), the common standard for federal legislative materials. Each level of a bill in USLM has its digital citation, or ‘identifier’. Currently, publishes bills in a form that it is possible to scroll to an individual provision. In the near future it should be possible to refer to section 1010(b)(i) of a bill and retrieve just that portion of the bill.

U.S. Code

The United States Code is an organized collection of the law maintained by the Law Revision Counsel (LRC), an independent organization that is part of the legislative branch. The Code is now published in USLM and is updated with the enactment of new laws in ‘release points’ that are published by LRC at Each portion of the Code in USLM also carries its digital citation in the form of an ‘identifier’.

Statute Compilations

Each law that is enacted becomes part of the ‘Statutes at Large’. The House Office of Legislative Counsel (HOLC) organizes these freestanding statutes and maintains up-to-date versions of the statutes that can be further amended by future laws. This collection is called the ‘Statute Compilations’, and many (but not all) of these statutes are also now published in USLM, with an embedded digital citation at each provision.

With these three data sources, and the tools described above, we are closer today than ever before to establishing that official, online, citeable public framework of law that so many of us have envisioned, perhaps at


For a post about digital citations, I intentionally left all of the references to the end, because I think it is important to have the uninterrupted narrative of the state of the federal law modernization. Here are references to some of the resources I mentioned in this post:

Version Control for Law: presentation at GitMerge 2019

XCiteDB: a version control database for XML a site that tracks bills and votes in Congress, and one of the earliest sites to publish federal bills in a digital format

Cornell’s LII: another trailblaziing site that publishes federal bills and law in a digital format

Official sites for the sources of federal law the official site for bills in Congress, published in XML (not yet USLM) by the Library of Congress

U.S. Code: the official site for the U.S. Code, published in various formats, including USLM, by the Law Revision Counsel

Statutes at Large: the official site for the Statutes at Large published by the Government Publishing Office

Statute Compilations: Statute Compilations in a number of formats, including USLM, published by the Government Publishing Office

USLM: the USLM XML data standard for federal legislative and regulatory documents; GitHub repository maintained by the Government Publishing Office, all available under the CC0 (no license) license

In addition to these, federal law consists of regulations, which are issued by the executive branch, and court decisions, issued by the judiciary. As I mentioned, there has been some progress in publishing regulations in USLM. I will discuss these sources in separate posts, but the principle of digital citeability holds: providing a citeable digital format for one source of law makes it modular and compatible with a coherent framework of digital law.