The purpose of this legislative text is to limit the authority to establish or expand national monuments in the United States, reserving that power exclusively for Congress. This is aimed at addressing concerns about what some perceive as excessive executive power in designating national monuments, which can restrict land use and access. The key provision of this legislation amends an existing law known as the Antiquities Act. It specifies that only Congress can create or expand national monuments, removing the ability of the President to do so unilaterally.