The United States is at its best when it is leading by example. When it became the first country to sign the Comprehensive Test-Ban Treaty in 1996, ratification by the US Senate was not taken for granted, but was certainly hoped for. Alas, that was not to be, as in 1999 the Senate voted 51-48 against the treaty with only four Republican Senators voting in favour (Arlen Specter of Pennsylvania, Jim Jeffords of Vermont, Gordon Smith of Oregon and Lincoln Chaffee of Rhode Island).
President Obama's declared commitment to nuclear non-proliferation, in Prague in 2009, and his administration's work on securing the new START treaty, once more raised expectations that the President would use his second term to persuade the Senate to move where it failed to go in 1999 and gain the required 67 votes to ratify the Comprehensive Test-Ban Treaty (CTBT), a treaty that makes it very difficult for countries to develop nuclear bombs for the first time, or for countries that already have them, to make more powerful devices.
As acting Under Secretary of State for Arms Control and International Security, Rose Gottemoeller stated in 2012: "A lot has changed since 1999, and people have not had a chance to really look at the CTBT and understand what it can accomplish for U.S. national security."
To overcome partisan divisions in the Senate and counter much misinformation concerning the treaty, numerous civil society reports by, for example, the Arms Control Association, National Academy of Sciences and the Nuclear Threat Initiative, have been produced in the last three years to acclimatise Senators ahead of an informed and constructive debate, potentially leading to a vote. Once again, this case must be made clear, and this case must be made now. Ratifying the treaty is in the national security interests of the United States - not only would it complete work begun by President Eisenhower and continued by President Kennedy, but it would marginalise any country that chooses to remain on such a political trajectory.
For the treaty to come into effect, the United States and 7 other countries - China, Egypt, India, Iran, Israel, North Korea, and Pakistan - must ratify and join the 159 countries that already have signed on, including every NATO ally of the United States, and Russia. With the threat of nuclear proliferation growing, the case for ratifying has never been stronger.
If the US ratifies the treaty, its current stockpile would remain intact, without any requirement for testing, as was clearly argued in the 2012 National Academy of Sciences report which stated: "Provided that sufficient resources and a national commitment to stockpile stewardship are in place, the committee judges that the United States has the technical capabilities to maintain a safe, secure and reliable stockpile of nuclear weapons..."
It is also worth noting that the US has not tested a single nuclear weapon in more than 20 years, while no signatory country has conducted a nuclear test explosion since signing. The CTBT would be a seal on what the United States and most other countries are already doing.
As Senator John McCain has intimated, the situation vis-à-vis monitoring and verification is also different than the situation in 1999. The largely completed International Monitoring System has proved its worth, detecting and identifying the 2006 and 2013 North Korean nuclear tests - the former at a juncture when only two-thirds of the system was operational.
Such international monitoring will help protect the United States - not hinder its security. As the National Academy of Sciences report conveyed, constraints placed on nuclear-explosion testing by the monitoring capabilities of the International Monitoring System and the capabilities of the US National Technical Means, "will reduce the likelihood of successful clandestine nuclear explosion testing, and inhibit the development of new types of strategic nuclear weapons." This can only create conditions for enhancing international stability while reinforcing US national security.
In the highly unlikely situation in which the United States deemed it necessary to return to test a new type of weapon meant to counter a particular type of nuclear threat, the United States could invoke the standard "supreme national interests" clause, withdraw from the CTBT, and conduct whatever testing might be required.
In his 2013 State of the Union speech, President Obama commented that "our ability to influence others depends upon our willingness to lead." The opposite may also be true. When the US refuses to lead, others may feel free or even motivated to stay out. However, there is little reason to believe that China would refrain from ratifying if the US did ratify, and the pressure would be strong on the remaining non-ratifying states to follow-suit.
By leading through example, President Obama and the Senate would be demonstrating political strength while opening the door for the other remaining states to ratify. In the end, ratification of the Comprehensive Test-Ban Treaty would demonstrate the United States' commitment to global leadership and strategic foresight. Ultimately, ratification would bolster US national security and make its citizens safer.
Dr Hans Blix is a former Swedish Minister for Foreign Affairs and former head of the International Atomic Energy Agency (IAEA); Des Browne (Lord Browne of Ladyton) is a former British Defense Secretary, and convener of the European Leadership Network. Sir Jeremy Greenstock is the chairman of the United Nations Association of the UK (UNA-UK) and a former British Ambassador to the UN; James Kearney is head of peace and security policy at UNA-UK, London.