North Korea’s latest nuclear test is bad news, both for Northeast Asia and for a world that needs to reduce its reliance on nuclear weapons. But international overreaction – with responses that raise rather than lower the temperature, and push the region closer to a nuclear arms race – would make bad news even worse. “Keep Calm and Carry On” – as the British government famously urged its citizens in 1939 – is advice that often lends itself to parody. But it is what needs to happen now.

North Korea’s latest action follows behavior over the last decade that makes Iran look positively restrained in comparison. It walked away from the nuclear Non-Proliferation Treaty in 2003; resisted serious negotiations within the framework of the Six-Party Talks established that year by the United States, China, Russia, South Korea, and Japan; tested nuclear explosive devices in 2006 and 2009 in breach of a global moratorium; conducted a series of increasingly provocative missile tests; ignored United Nations Security Council resolutions and sanctions; sank a South Korean navy ship and shelled one of its islands in 2010; and maintained a steady flow of belligerent rhetoric.

All of this has jarred regional nerves yet again, in South Korea and particularly in Japan. There is new talk about the resources that may need to be mobilized to counter what is perceived as an increasingly sophisticated threat. It is still not permissible in polite company to talk about these front-line states acquiring their own nuclear weapons. But putting U.S. weapons back into South Korea, acquiring real missile capability, allowing the reprocessing of spent nuclear fuel, moving closer to breakout capability – all of these steps now have their advocates, and these voices will grow louder.

Nor has North Korea’s behavior done anything to help the cause of global non-proliferation and disarmament. It has successfully thumbed its nose at international pressure, becoming a beacon to small, vulnerable, badly behaved states whose leaders want to believe that nuclear weapons will buy them immunity from intervention, and that Iraq’s and Libya’s biggest mistake was to fail to acquire them.

Major downsizing of the U.S. nuclear arsenal, which President Barack Obama wants to achieve, will become politically more difficult. America’s tentative steps toward reducing the role of nuclear weapons in its overall security strategy, including defending its regional allies, will be harder to implement.

This will all translate, inevitably, into calls for more toughness toward North Korea – less diplomacy and more sanctions, punitive measures and isolation. How can anyone talk about returning to talks, offering incentives or normalizing relationships with a regime that is so demonstrably recalcitrant? Shouldn’t we fight fire with fire?

Less inevitably, but more alarmingly, there may now be greater tolerance for those who argue that a country has a right to defend itself against existential threats with equally threatening weapons, or that a world of multiple nuclear powers would be less, not more, dangerous – with threats deterred and risk neutralized.

Such responses would be serious overreactions. At a general level, Henry Kissinger, George Shultz, William Perry, and Sam Nunn were right to argue that, whatever the case might have been for nuclear weapons during the Cold War, a 21st-century world of multiple competing nuclear powers would be one of massively enhanced global risk.

The core message of the NPT must continue to resonate: So long as anyone has nuclear weapons, others will want them; so long as anyone has them, they are bound one day to be used, by accident or miscalculation, if not by design; and any such use would be catastrophic not just for the states immediately affected, but for life on this planet. For that message to resonate, the major nuclear-armed states must not only remain committed to non-proliferation, but also get serious about disarmament.

In the case of North Korea, the world must of course register its displeasure. There will, and should be, Security Council condemnation and measures taken to cause the regime, if not its long-suffering people, genuine pain. But, alongside all of that, the door should be kept wide open for negotiation.

Before rushing to conclude that the regime in Pyongyang is one with which no productive normalization and denuclearization talks will ever be possible, we need to revisit the record. World leaders signed the Agreed Framework with North Korea in 1994 (I was engaged in the process as Australia’s foreign minister), but we dragged our feet in building the nuclear reactors and delivering the heavy fuel oil promised, partly owing to a widespread belief that the regime’s collapse was imminent.

The diplomatic trajectory re-established a few years later was halted by George W. Bush’s “Axis of Evil” declaration in 2002. When a potential new deal was negotiated by the U.S. State Department in 2005, U.S. Treasury officials slammed that window shut by warning the world’s banks against conducting transactions with any North Korean entity. The “Sunshine Policy,” which for a decade sustained hope of North-South reconciliation, ended abruptly with President Lee Myung-bak’s election in South Korea in 2008.

The North Koreans are erratic, unpleasant, irresponsible and unhelpful. But they don’t bear all the blame for the past, and are not behaving completely irrationally. New administrations, free of their predecessors’ baggage, are in place in all of the relevant regional capitals. If they, the U.S., and Russia stay calm, place enough on the table, and demand the same from the other side, diplomacy might move forward, and the future might not be irredeemably bleak.

Gareth Evans was Australia’s foreign minister from 1988 to 1996, and was president of the International Crisis Group from 2000 to 2009. He has co-chaired the International Commissions on Intervention and State Sovereignty and on Nuclear Non-Proliferation and Disarmament. THE DAILY STAR publishes this commentary in collaboration with Project Syndicate © (www.project-syndicate.org).