The U.S. government last week released the Nuclear Posture Review, a congressionally mandated report that explains its thinking about nuclear weapons and nuclear policy. The NPR reflects the Trump administration’s belief that the world is increasingly shaped by great power competition and that nuclear arms are needed to promote security and stability. The world is more dangerous than it has been for a long time, but there are justifiable concerns that this new approach could magnify dangers, not reduce them.
Every NPR has three goals: to deter adversaries, to reassure allies and to create conditions that promote disarmament. Arguing that the world has changed significantly since the last NPR was written in 2010, the latest report is oriented more toward deterrence, while retaining a commitment to nonproliferation and arms control. The authors of the NPR devote considerable space to the reassurance of allies, and it focuses on strengthening extended deterrence. It supports ongoing, close collaboration with allies and partners to ensure that strategies are tailored to their specific situation.
The new document acknowledges the long-standing U.S. goal to reduce the numbers of nuclear weapons — its stockpile of nuclear weapons has been cut by more than 85 percent since the Cold War peak — but seems to reverse the effort of previous administrations to reduce the salience of nuclear weapons in U.S. defense policy. That change is based on the belief that other countries have been modernizing arsenals and doctrines, and as a result have acquired weapons systems that can be deployed in crises. The United States must prevent them from believing that nuclear weapons will allow them to prevail in those situations. To that end, the NPR calls for the creation of two new capabilities: a low-yield warhead for submarine-launched ballistic missiles and a nuclear-capable submarine-launched cruise missile. Low-yield nuclear weapons have long been part of the U.S. arsenal; nuclear-tipped cruise missiles were once deployed by the U.S. but they were shelved years ago, a move that troubled some Japanese strategists.
Critics charge that the approach of U.S. President Donald Trump’s administration will increase the likelihood of nuclear war. First, they argue that deploying lower-yield weapons will lower the nuclear threshold: Governments will be encouraged to use them in a conflict since they will not threaten a strategic exchange. Advocates counter that precisely because lower-level nuclear options exist — without them, a country can only respond with its strategic arsenal — adversaries will not be tempted go nuclear to terminate a conflict, or “escalate to de-escalate.”
Second, critics point out that adversaries will not know what warhead is on a submarine-launched missile. The platform and the missile are used for both conventional and low-yield nuclear weapons. A wary adversary will not wait to find out which it is and will deploy its nuclear forces before they are destroyed. The temptation to “use it or lose it” is strong.
Third, there is the charge that the new NPR allows the U.S. to use its nuclear weapons in response to non-nuclear attacks. This policy is not new. Washington has long maintained that its nuclear weapons could be used to respond to any attack with weapons of mass destruction, including biological or chemical weapons. The new twist is their possible use for a cyberattack on critical infrastructure. It is long-standing policy that the U.S. would consider the use of nuclear weapons in extreme circumstances to defend the vital interests of the U.S., its allies and partners. A U.S. official noted that “the NPR clarifies long-standing policy that extreme circumstances could include significant nonnuclear strategic attacks,” adding that the “clarification is stabilizing. It lowers the risk of nuclear use by anyone.” He emphasized that the context of an attack is important.
There is a fourth way in which the new NPR could increase the risk of nuclear use. Modernization of the nuclear arsenal will cost a lot of money; by one estimate, it will consume 3.7 percent of the Defense Department budget at its peak in 2029. Given straitened fiscal conditions, that money will have to come from other defense accounts, most likely conventional forces. Reducing conventional capabilities in turn increases the likelihood of resorting to nuclear weapons in a crisis.
The Japanese government, like many U.S. allies, is pleased with the new NPR. The emphasis on extended deterrence, reassurance and tailored deterrence is welcome. The new document does not refer to “strategic stability,” a phrase in President Barack Obama’s NPR that suggested that China would have a second-strike capability. As a result, Beijing could threaten the U.S. homeland if Washington honored its commitment to defend Japan. That was anything but reassuring. That change is welcome. The prospect of early nuclear weapons use in a crisis is not.