Trilateral negotiations on a nuclear test ban between the Soviet Union, the United Kingdom and the United States commenced once again in late 1977. The treaty would include a seismic monitoring station, but only On-site Inspections (OSI) of a voluntary nature. The Soviet Union objected to the unlimited duration of the treaty as proposed by the other two parties, noting that non-signatory states could continue to improve their nuclear arsenals. In response, US President Carter, along with the United Kingdom, proposed a treaty lasting for three years. Questions then arose about the practicality of establishing an extensive monitoring system for a treaty that might only last for a limited duration of time. Furthermore, it would likely be difficult politically to conclude a new treaty after the initial three-year period. The Conference on Disarmament (CD) received regular progress reports from negotiators involved in the continuing trilateral talks. Disagreements over OSI did not appear to be an issue. Nonetheless, the parties opted not to release the draft text.

National sovereignty was always a contentious issue whenever parties discussed the protocols of an OSI. A Swedish draft treaty in 1983 called for a group of experts selected from parties to the treaty to conduct the OSI on a purely fact-finding basis. Experts were prohibited from analyzing or speculating about the cause of the event. In 1991, Sweden advanced this issue by issuing a draft treaty calling for the establishment of a board of governors to authorize an OSI request from a state party to the treaty. This compromise aimed at reconciling the differences between parties over the voluntary vs. mandatory nature of OSI.