States currently manage the risks of nuclear weapons through a range of measures that, together, have prevented the worldwide spread of these weapons of mass destruction, but have not significantly reduced the risk of catastrophic use.   

The pillar of nuclear military strategy is deterrence, whereby nuclear-armed states threaten to retaliate against other states’ use of nuclear weapons against them. This doctrine is considered by some to be an effective way of preventing nuclear war. The fact that no nuclear weapons have been used in any conflict since 1945, however, suggests that an emerging moral norm may also play a role in discouraging their use.  

International cooperation, beginning with the 1963 US-Soviet treaty to ban atmospheric testing, along with subsequent US-Soviet/Russian bilateral treaties and agreements has reduced and stabilized nuclear arsenals from a high of 68,000 in the late 1980s to about 15,000 today. In addition, the 1970 Nuclear Non-proliferation Treaty (NPT) has prevented the development of nuclear weapons in all countries beyond the original five (United States, Soviet Union/Russia, United Kingdom, France and China) with the exception of India, Pakistan, North Korea, and probably Israel. Altogether, some 25 governments have given up their nuclear weapons programs, including South Africa, Libya, Belarus, Kazakhstan, and Ukraine. Another 15, like Canada, Brazil, and Argentina, have contemplated programs but not embarked on them, in keeping with their responsibilities under the NPT.

"25 to 40 governments have willingly given up their nuclear weapons programs."

The UN Security Council, whose permanent members include the five recognized nuclear weapons states, enforces the Nuclear Non-proliferation Treaty in partnership with the International Atomic Energy Agency (IAEA). Although the IAEA was established primarily to promote and oversee the development of civilian nuclear power, under Article III of the NPT, the IAEA is entrusted with verifying adherence to the Treaty. Parties to the NPT regularly report to the IAEA about the means used to safeguard and secure enriched uranium and plutonium used in civilian power plants, as well as steps to prevent the use of nuclear materials for bombs. 

Several states have not complied with their NPT obligations and faced penalties from the international community. Iraq embarked on a nuclear weapons program, but after nuclear bomb technology was discovered in 1991, the program was destroyed by a special UN Security Council-mandated force. In the case of Iran, international economic sanctions were applied when suspicions arose about its possible pursuit of nuclear weapons. To prevent Iran from acquiring them, multilateral negotiations produced the 2015 Joint Comprehensive Plan of Action. It mandated reduction of the means to enrich uranium to a minimal level and only allowed enrichment to below weapons-grade. It also ensures continuous monitoring by the IAEA of Iran’s civilian nuclear program. 

The difficulties of enforcing the NPT when countries do not wish to cooperate, however, are illustrated by the case of North Korea, which announced its withdrawal from the NPT in 2003. It has since conducted at least six nuclear weapons tests. Despite international pressure, including economic sanctions, North Korea continues its nuclear program in the belief that it will deter aggression by the United States.

The fact that decisions about nuclear weapons are made in utmost secrecy, outside of democratic policy processes, poses substantial obstacles to nuclear governance in the public interest. Yet citizen protests in the United States, Europe and Japan from the 1950s through the 1980s have raised awareness of the risks and pressured governments to curtail nuclear weapons programs. For example, mass protests in the 1980s by the European Campaign for Nuclear Disarmament and the US Freeze movement pressured political leaders in Europe, the Soviet Union and the United States to enact major reductions in nuclear arsenals and, some even suggest, contributed to the end of the Cold War.

Recently, an international humanitarian movement worked with non-nuclear weapons states to introduce a UN treaty banning all nuclear weapons. One hundred and thirty-five of the 193 member countries participated in the 2017 UN treaty negotiations; 122 countries voted in favour of the final treaty, one against, and one country abstained. As of April 2018, 54 countries have signed the treaty and seven have ratified it, adapting their national legislation to comply with its provisions. The treaty, which is indefinitely open for signing, will take effect when 50 nations have ratified it. Not since the Nuclear Non-proliferation Treaty of 1970 have states taken such dramatic and collective action to prohibit possession of nuclear arsenals.

At the same time, unfortunately, re-emerging nationalism is spurring the nine nuclear weapons states – none of which participated in or voted on the UN ban treaty – to redesign, increase and, in some cases, lower the threshold to use their nuclear weapons. Such actions reinforce beliefs about the purported utility of nuclear weapons, undermine international cooperative efforts to reduce the risks, and increase the probability of catastrophic nuclear war.