Universal Copyright Convention (UCC) is an international instrument which was drawn up in 1952 under the auspices of UNESCO.
Thus the United States would have to make several major modifications to its copyright law to become a party to the Berne Convention.
Eventually, the United States became willing to participate in the Berne Convention and change its national copyright law as required.
Under the Second Protocol of the Universal Copyright Convention (Paris text), protection under U.S. copyright law is expressly required for works published by the United Nations, by UN specialized agencies and by the Organization of American States (OAS).
Since almost all countries are either members or aspiring members of the World Trade Organization (WTO), and thus comply with the Agreement on Trade-Related Aspects of Intellectual Property Rights Agreement (TRIPS), the UCC has lost significance.