People sometimes forget that the boy who cried wolf ended up being eaten. True, nobody has been killed by a nuclear weapon since the attacks on Hiroshima and Nagasaki 65 years ago this month. And with Cold War tensions long past, it's all too easy for policy-makers and publics to resist the doomsayers, be complacent about the threats that these weapons continue to pose, and to regard attempts to eliminate them, or contain their spread, as well-meaning but futile.
But the truth is, it's sheer dumb luck - not statesmanship, good professional management or anything inherently stable about the world's nuclear weapons systems - that has let us survive so long without catastrophe. With 23,000 nuclear weapons (equivalent to 150,000 Hiroshimas) still in existence, more than 7,000 of them actively deployed and more than 2,000 still on dangerously high launch-on-warning alert, we can't assume our luck will hold indefinitely.
We know now - with multiple revelations about human error and system breakdown on both the American and Russian sides during the Cold War years and since - that even the most sophisticated command and control systems are not foolproof. We know that some of the newer nuclear-armed states start with systems much less sophisticated than these. And we know that, across the spectrum of sophistication, the risk of destabilizing cyber attack beating cyber defence is getting ever higher.
So it should be obvious that maintaining the status quo is intolerable. Moreover, there's the real risk of proliferation, especially in the Middle East, multiplying the dangers that nuclear weapons will be used by accident or miscalculation as well as design.
There's also the sometimes exaggerated but unquestionably non-negligible risk of non-state terrorist actors getting their hands on insufficiently secured weapons or fissile material and exploding a bomb in a major population centre. And there's the disconcerting prospect that new civil nuclear-energy players will insist on building uranium-enrichment or plutonium-reprocessing plants of their own, rightly described as "bomb starter kits."
President Barack Obama came to office alert to all these threats and determined to eliminate them. His leadership inspired hope that more than a decade of sleepwalking was behind us, and brought some modest gains over the past 18 months. They include the conclusion of the U.S.-Russia new START treaty, which would reduce deployed strategic weapons; some modest limitations on the role of nuclear weapons in U.S. nuclear doctrine; a Washington summit that reached agreement on the implementation of improved nuclear-security measures; and consensus at the recently concluded pentannual Nuclear Non-Proliferation Treaty Review Conference on useful steps forward, including a 2012 conference on achieving a nuclear-free zone in the Middle East.
But START treaty ratification is going nowhere fast in the U.S. Senate, and progress on other key issues has been slow or shaky: bringing the Comprehensive Test Ban Treaty into force; starting negotiations on a new treaty to ban the production of fissile material for nuclear weapons; strengthening the non-proliferation regime with effective measures to detect violations and deter treaty walkouts; reaching agreement on some form of international management of the most sensitive aspects of the fuel cycle; and, above all, starting new rounds of disarmament talks involving all eight nuclear-armed states.
Arms control and disarmament is a grinding, unglamorous business that brings few quick returns. With domestic issues and re-election anxieties now dominating most political agendas, it will be all too easy for commitment to wane. If that's to be avoided, continued leadership from the top - above all, from Mr. Obama and Russian President Dmitry Medvedev - will be indispensable. But there are a number of major contributions that less powerful states and leaders, as well as civil-society organizations, can make.
The most important task is for those with credible voices to take every opportunity to bridge the complacency gap. The messages must be stark: Nuclear weapons are not only the most indiscriminately inhumane weapons ever invented, but the only ones capable of destroying life on this planet as we know it. Carbon dioxide can also kill us, but not as quickly as bombs.
The second major task is to set a clear global disarmament action agenda - with credible timelines and milestones. It's probably too difficult right now to set a reliable target date for getting all the way to "global zero": There are still too many technical problems of verification and enforcement to work out, as well as the obvious geopolitical and psychological ones. But it's not incredible to set a date such as 2025 as a target for minimizing the world's nuclear arsenal to less than 10 per cent of its current size, with very few weapons actually deployed, and their role in all states' military doctrine dramatically reduced.
And it's not too early to begin work on crafting a new Nuclear Weapons Convention that provides a workable framework for multilateral negotiations, and on devising an independent high-level monitoring mechanism that would spell out clear benchmarks for progress, track how they are being met, and create real pressure for change.
These are all recommendations of the International Commission on Nuclear Non-Proliferation and Disarmament. As the world commemorates the 65th anniversary of the bombing of Hiroshima and Nagasaki, we should recognize that our luck is running out - and take them seriously.
Gareth Evans, a former foreign minister of Australia and president emeritus of the International Crisis Group, is co-chair of the International Commission on Nuclear Non-Proliferation and Disarmament and professorial fellow at the University of Melbourne.