EXPANDING THE REGISTER The National Historic Preservation Act
authorized the Secretary of the Interior "to expand and maintain
a national register of districts, sites, buildings, structures,
and objects significant in American history, architecture,
archeology, and culture, hereinafter referred to as the National
Register...." The National Register was at the core of the act:
nearly everything else was aimed at identifying, preserving, and
protecting what would be included in it. The decisions made in
implementing this provision were therefore basic to the national
historic preservation program over the next two decades. Those
in the National Park Service charged with further defining,
expanding, and maintaining the National Register had aided or
witnessed the drafting of the act's language and were familiar
with the testimony of its proponents during the legislative
process. From this legislative history they derived and
incorporated certain axioms that were not obvious from the act
alone. The first of these