US nuclear arms shift could raise risk of inadvertent conflict
Policies on ‘sole purpose’ or ‘no first use’ sound appealing but would weaken security guarantees
As Mikhail Gorbachev and Ronald Reagan declared in 1985, “a nuclear war cannot be won and must never be fought”. Alongside climate change and pandemic disease, nuclear weapons represent a risk to humankind’s continued existence on our planet. But President Joe Biden’s upcoming review of US nuclear posture — which is expected to clarify the circumstances in which its weapons might be used — could bring inadvertent and unwanted consequences.
Biden has already hinted that he is considering a “sole purpose” policy, a pledge that the US would use nuclear weapons only in a narrowly prescribed set of circumstances. “I believe that the sole purpose of the US nuclear arsenal should be deterring — and, if necessary, retaliating against — a nuclear attack,” he wrote in March 2020. “As president, I will work to put that belief into practice.” A number of other influential voices are now encouraging a move in this direction, or even a shift to a policy of “no first use” of nuclear weapons. For the sake of Nato unity, these ideas must be resisted.
“No first use” sounds appealing, and its advocates argue that the US can set an example to other nuclear powers that would, in time, reduce the threat of nuclear conflict. They are wrong. There are three reasons why both this and “sole purpose” would undermine deterrence, divide Nato and increase the risk of conflict.
First, a US declaration would be treated with scepticism by potential adversaries — because authoritarian regimes are likely to judge others by their own standards — and could even encourage them towards military aggression if the threat of nuclear reprisals is lifted. Paradoxically, changing the present definition of nuclear deterrence would increase the risk of a major conventional conflict that could return us to the era of mass civilian casualties last seen in the 20th century.
Second, Nato as a nuclear alliance is deliberately ambiguous about the circumstances in which it might authorise the deployment of nuclear weapons to deter attacks on the territory or interests of its members. In the aftermath of the cold war, when there was no credible conventional threat to Nato’s European allies, the alliance reduced its emphasis on nuclear deterrence. But Russia’s invasions of Georgia in 2008 and Ukraine in 2014, and the massive boost to Moscow’s conventional and nuclear capabilities in the past few years, have necessarily raised the profile of nuclear weapons in Nato’s defence posture.
While nuclear ambiguity may be uncomfortable, it is necessary in order to reduce the temptation for adversaries to “game” our deterrence strategy by taking actions that will fall just short of provoking a military response.
Third, at a time of heightened tension due to Russia and China’s growing military power and threatening behaviour, a US declaration of “sole purpose” or “no first use” would unsettle Washington’s allies in Europe and the Asia-Pacific. By casting doubt on its security guarantees, the US would run the risk of making its allies and friends more susceptible to coercion, or of driving them to develop nuclear weapons of their own as a form of insurance. And that would potentially kickstart further nuclear proliferation and add to the risk of pre-emptive actions by Russia and China.
Advocates of change are right to say that progress on nuclear disarmament is painfully slow. But it will be achieved only by skilful diplomatic management of the conflicting ambitions and interests of the major powers. Painstaking efforts are needed to revive bilateral and, in time, multilateral steps towards verifiable nuclear disarmament and the prevention of proliferation. Eye-catching gestures from the US such as declarations of “sole purpose” or ‘no first use’ would undermine the Nato alliance and lead only to greater instability and insecurity.