Since the inception of the International Monitoring System (IMS) and the Prototype International Data Center in 1995 there have been three claims of nuclear testing by three governments. All have been false, which was demonstrated with the use of the IMS.

In August 1997 the US government accused Russia of conducting a nuclear test at their Novaya Zemlya test site. Seismic data from the IMS and other networks was used by many seismologists to demonstrate that the seismic signal infact originated out at sea, rather than at the test site, and had the characteristics of an earthquake. In May 1998 India and Pakistan announced their entry into the nuclear club with a series of tests. Again IMS data available to anyone via the internet, could be used to demonstrate the shortcomings of their test claims.

During the recent US Senate debate on the Comprehensive Test Ban Treaty, however, the utility of the IMS was called into question. While the US maintains its own nuclear testing verification capability, it is not clear that it is superior to the IMS. IMS data was used to demonstrate that the Novaya Zemlya event was an earthquake, while US government agencies, using their own capabilities, initially claimed it was a nuclear test. The IMS also provides the only verification capability for many nations. When the will of individual nations to build nuclear weapons is often driven by the paranoia that others are doing the same, the availability and transparency of the IMS makes it a valuable tool to reduce nuclear proliferation.

Following the defeat of the treaty continued US funding for the IMS has become uncertain. Since the US funds a significant proportion of the operating costs, this makes the future of the IMS uncertain. For the reasons detailed above continued operation of the IMS is in the interest of US national security, and every effort should be made to maintain this capability. Dismantling the IMS would also strike a terminal blow to the current and future Comprehensive Test Ban Treaties.