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.  

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.

"The pillar of nuclear military strategy is deterrence, whereby nuclear- armed states threaten to retaliate against other states' use of nuclear weapons against them."

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 weapons were 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, allowing enrichment only to below weapons-grade. It also ensured continuous IAEA monitoring of Iran’s civilian nuclear program.

As part of an unravelling of nuclear governance, however, the United States has pulled out of the Joint Comprehensive Plan Of Action and Iran has increased production of enriched uranium beyond that stipulated in the agreement. Even more consequential, the United States has announced its abrogation of the 1987 Intermediate Range Nuclear Forces Treaty with Russia that banned a class of missiles with nuclear weapons capability.

In addition, the United States has not yet announced its interest in working with Russia to extend the 2010 New START, an agreement that places a cap on American and Russian arsenals with provisions for robust inspections. Russia and the United States have each declared their intentions to use nuclear weapons, even if nuclear weapons are not used against them first.

These actions, along with North Korea’s continued production of nuclear weapons, despite international economic sanctions, suggest that the norms of restraint may not be as strong as in the past. In fact, a new nuclear arms race is under way among all of the nuclear weapons states that reinforces the utility of nuclear weapons in war- fighting and increases the risk that these weapons will be used.

This new arms race underscores the difficulties of enforcing the NPT when countries do not wish to cooperate. The original treaty suggested a bargain whereby states without nuclear weapons would not acquire them but would have access to civilian nuclear power. In exchange, the states with nuclear weapons pledged to disarm when conditions warranted. Many believed that the end of the Cold War was such a time, and yet, while nuclear arsenals have radically decreased in Russia and the United States, the recent reversal in doctrine and rhetoric suggest that these and other nuclear weapons states have no intention at present of eliminating their nuclear arsenals.

Even as formal treaties and informal norms of restraint are eroding, however, non-nuclear weapons states have introduced 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 favor of the final treaty, one against and one country abstained. As of December 2019, 80 countries have signed the treaty and 34 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

Unfortunately, re-emerging nationalism is spurring the nine nuclear weapons states – none of which participated in or voted on the UN ban treaty – to modernize, increase and 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 seriously increase the probability of catastrophic nuclear war.