The
Moon Treaty (officially the Agreement Governing the Activities of State on the Moon and Other Celestia Bodies) is an international treaty that was intended to expand on the existing Outer Space Treaty and other space-related treaties to establish an international regime for the use of space, much as the United Nations Convention on the Law of the Sea attempted to establish an international regime governing the ocean, especially international waters and seabeds. However, unlike the ratification of UNCLOS by the vast majority of the international community (with, of course, the important exception of the United States), the Moon Treaty never gained much traction, with only two spacefaring states (France and India) even signing it, and none ratifying or acceding to it (with the partial exception of Kazakhstan, which contains Baikonur Cosmodrome but doesn't have an independent orbit-capable space program). The primary reason for this is that the Moon Treaty has several provisions which make it difficult for states to develop extraterrestrial resources to their benefit, similar to provisions in UNCLOS regarding the seabed; in particular, it explicitly forbids private individuals or organizations from owning or claiming celestial bodies, and requires the creation of an international regime similar to the International Seabed Authority to manage and share the produce of resource extraction from celestial bodies.
However, initially the United States government supported the Moon Treaty, and played a fairly important role in negotiating it. Before it could be signed by President Carter, though, the L-5 Society--a group promoting the ideas of Gerard K. O'Neill, particularly the development of space industrialization as a prelude to large-scale space colonization--mobilized in opposition, bringing the treaty to the attention of campaigners against UNCLOS seafloor mining provisions and using them to dissuade the State Department from proceeding with the treaty. Reagan, of course, was opposed to any such international treaty, and without Soviet (or later Russian) support, the result was a dead treaty.
But! L-5 opposition to the treaty was actually a fairly near-run thing, and tangled up in the politics of who was to succeed the then-president of the Society. Several board members either thought that opposing the treaty was a waste of money or actively favored the passage of the treaty, and were therefore disinclined to go along with opposing it. It is therefore plausible to imagine the L-5 Society not becoming involved. Although it's possible that the UNCLOS opponents would still mobilize against the Moon Treaty to avoid having a precedent to deal with, it's also possible that it would fly more or less under the radar until it was signed.
Thus, suppose that it is signed in early 1980. What, then, happens?