The main assessments and conclusions to emerge from the workshop and how they relate to the prospects of future CTBT ratification are summarized below:

• There was widespread—but not unanimous—agreement that the U.S. nuclear stockpile can be certified as safe, secure, and reliable without a resumption of nuclear explosion testing. This assessment is primarily based on ongoing improvements to the Department of Energy (DOE) Stockpile Stewardship Program (SSP) and the enhanced understanding of nuclear weapons it has produced in the last ten years. The possible increase in the functional lifetime of U.S. nuclear weapons, as described in DOE studies of nuclear material and life extension programs and assessments of that work by outside expert groups, factors prominently in this judgment.
• The ability of SSP to ensure the reliability of the nuclear stockpile in the absence of testing is tied to maintaining the infrastructure of and expertise in the U.S. nuclear weapons complex. There was strong concern that the nuclear complex—including the national security laboratories—does not have the resources it needs to fulfill its mission.
• The military has more to consider than just the reliability of the nuclear warhead. Reliability is a function of the performance of the nuclear weapon in each of the deployed delivery systems across the specturm of the entire mission. The method to characterize the performance of a weapon system could be adjusted without reducing the ability of the military to carry out nuclear missions.
• Most of the Comprehensive Test Ban Treaty Organization (CTBTO) Preparatory Commission’s International Monitoring System (IMS) is certified or in place and the capability of the IMS is improving ahead of the schedule envisioned when treaty negotiations concluded in 1996.
• The IMS was able to better assess its “real-world” capabilities when it successfully detected North Korean nuclear tests in 2006 and 2009, and field-tested its On-Site Inspection (OSI) capability for the first time in 2008.
• Since the treaty was negotiated, there have been important improvements in the ability of systems outside the IMS to detect nuclear explosions. This additional capability is held in National Technical Means (NTM), in auxiliary IMS stations, and in regional seismic monitoring networks not linked to the IMS and is significant since the treaty allows for the incorporation of additional technologies not specified in the treaty. In addition, novel underground explosion detection technologies such as the satellite-based interferometric synthetic aperture radar (InSAR) can now sometimes measure changes in the elevation of the surface of the earth down to the centimeter level. The adoption and incorporation of these additional capabilities and other systems outside the IMS could mean that nuclear explosion detection may continue to improve significantly in the future.
• There remains considerable uncertainty in the Obama administration about whether the technological advances of the last ten years will be sufficient to change the Senate’s views enough to obtain the minimum sixty-seven “yes” votes required to ratify the treaty. Many factors—not all of them related to the treaty or even nonproliferation—will determine when the Senate Foreign Relations Committee decides to present the CTBT for debate and consideration for a second time.
• Today, from the perspective of the Obama administration, CTBT ratification is an important part of the nonproliferation agenda. However, the administration has not yet begun a robust outreach effort to make its case for CTBT ratification. In fact, the opponents of ratification have forced the administration into a defensive posture by narrowly defining the debate around the technological capabilities needed to ensure the safety, security, and reliability of the U.S. nuclear stockpile and the ability of the IMS to detect nuclear tests.
• The completion of the Nuclear Posture Review, a new National Academy of Sciences study on technical issues related to the CTBT, and a new National Intelligence Estimate on the CTBT as well as the anticipated START follow-on agreement will help shape the ratification timeline for the administration. Their contents will be central to the anticipated ratification debate.
• Since treaty opponents have been able to shape the debate so far, the Obama administration must clearly tie CTBT ratification into the bipartisan consensus on nonproliferation. Specifically, it needs to change the focus from technological capacity to national security. It must also be prepared with strong and clear explanations of the technical aspects of the debate, which will likely dominate any Senate discussion of the treaty.