1950 U.S. federal census records are going to be released for public view this year, because it has now been 72 years since that census was taken, and the National Archives follows what is known as the 72-Year Rule. The story of why the 72-Year Rule exists is an example of how history actually happens and how a government comprised of independent agencies and institutions functions.
As all genealogists but few other people are aware, there was a fire in 1921 in which most of the 1890 census was destroyed. This, among other things, caused many people to think about the haphazard way other government records were stored, often in basements, attics, abandoned buildings, or any other available space. In 1926, Congress passed a law providing for several new government buildings to be built, including one for a not yet existing National Archives, where important records could be safely preserved.
Of course it took several years to design and construct the building. When it was nearly finished, in 1934, the National Archives as an agency and the position of Archivist of the United States were created, and in 1935, the first Archivist and his staff set about finding, cleaning, and restoring records and bringing them to the building.
One of the larger tranches of records transferred to the National Archives in its early years included all the oldest census records, from 1790-1870, which came from the Census Bureau in 1942 and were released to the public later that year. 1942 happened to be 72 years after 1870, which set a precedent, but was not yet a rule.
In 1950, Congress passed a law calling for more explicit regulations on records management, and required that restrictions on public access be limited to 50 years, unless the Archivist determined that a longer period was necessary. Negotiations between the Census Bureau and the National Archives ended in an agreement, in 1952, that census records would be transferred from the Census Bureau to the National Archives as soon as they were no longer needed by the Census Bureau, and that they would be made publicly available after 72 years, but only to professional researchers or to relatives of the people listed.
The official letters between the Census Bureau Director and the Archivist do not make clear why they chose 72 years, but it was 1952, 72 years after the 1880 census was taken, and since the 1870 census was released in 1942, it might have been as simple as convenience. In any case, the 1880 census was released in 1952, and what fragments remained of the 1890 census in 1962.
By 1972, however, there was considerable public debate about privacy concerns, and the release of the 1900 census was delayed for a year, and then released under very tight restrictions, available on a limited basis only to certain kinds of researchers and with no copies allowed. Debate continued for several years, with laws proposed that ranged from releasing such records after 50 years to keeping them tightly restricted forever. The National Archives leaned in the direction of giving more people access, and the Census Bureau leaned in the direction of keeping the records restricted, and many others joined the debate.
Finally, in 1978, a sort of compromise was reached, part of which was to go back to the correspondence from 1952 and use that as a basis to set the length of time. That is when the 72 years actually became codified in law. It’s not necessarily permanent, but any change must be agreed by the Census Bureau and the National Archives.
Now, census records are made available online, and genealogy websites race to get indexes done as soon as possible, so very few restrictions on access remain. The debate over privacy concerns versus access for research continues, however, and things could change. For the time being, the 72-Year Rule remains in force, one small example of how history is shaped both by the decisions of individuals and by the circumstances in which they find themselves.
If you want to know more, you can find pertinent information from the Census Bureau here, from the National Archives here and here, and from the very informative article here.