Our nuclear future would take a significant turn for the worse if Beijing and New Delhi begin to mimic Cold War thinking about the utility of nuclear weapons. So far, they haven't. New Delhi waited 24 years in between nuclear tests, and Beijing took about as long to begin sea trials of second-generation ballistic missile-carrying submarines. Both have issued "No First Use" declarations, focused on economic metrics of national influence, and generally dealt with nuclear deterrence in ways that are hard for Washington and Moscow to comprehend. Their parallel nuclear postures are all the more remarkable because they have fought a limited war over a longstanding border dispute. Can the uncommon strategic constraint of these two rising powers continue? Important tests lie ahead, like those facing Washington and Moscow in the late 1960s and early 1970s.

As of mid-2014, the authors estimate that there are approximately 16,300 nuclear weapons located at some 98 sites in 14 countries. Roughly 10,000 of these weapons are in military arsenals; the remaining weapons are retired and awaiting dismantlement. Approximately 4,000 are operationally available, and some 1,800 are on high alert and ready for use on short notice. The largest concentrations of nuclear weapons reside in Russia and the United States, which possess 93 percent of the total global inventory. The United States today stores nuclear weapons at 18 sites, including 12 sites in 11 states in the United States and another six sites in five European countries. There is considerable uncertainty about the number of Russian nuclear weapons storage

sites, but the authors estimate that Russia today stores nuclear weapons permanently at 40 domestic locations.

That nuclear negotiations between Iran and the P5+1 (China, France, Russia, the UK, U.S. and Germany) were extended beyond the 20 July 2014 deadline was neither unexpected nor unwelcome. The parties had made enough headway to justify the extension, which was envisioned in the Joint Plan of Action (JPOA) that was signed in November 2013 and came into force in January, but given the political and technical complexity, they remain far apart on fundamental issues. Unless they learn the lessons of the last six months and change their approach for the next four, they will lose the opportunity for a resolution not just by the new 24 November deadline but for the foreseeable future. Both sides need to retreat from maximalist positions, particularly on Iran's enrichment program. Tehran should postpone plans for industrial-scale enrichment and accept greater constraints on the number of its centrifuges in return for P5+1 flexibility on the qualitative growth of its enrichment capacity through research and development.