Strategic deterrence—underpinned by credible nuclear arsenals—has underwritten the relative peace among the world’s nuclear powers for more than half a century. During the Obama administration, a slow commitment to modernizing our nuclear capabilities coupled with a dangerous absence of clear strategic dialogue—which left uncertainty about the United States’ willingness to use nuclear weapons even if attacked with them—began to erode the credibility of the U.S. deterrent. At first glance, the 2018 Nuclear Posture Review (NPR) appears to right the nation’s strategic ship by committing to modernizing our nuclear arsenal and by rightly positioning nuclear strategy at the center of the nation’s effort to deter a great power war.
Unfortunately, the NPR’s unnecessary call for developing more low-yield nuclear assets and its cavalier lowering of the threshold for nuclear use—despite its claim to the contrary—undermine the NPR’s central thesis, which is “to deter threats and reassure allies.” Putting tailored, flexible nuclear warfighting options on the table—and brandishing their use for non-nuclear strategic attacks such as cyber intrusion—discounts the certainty of massive retaliation in response to an existential threat to the United States and our allies. This not only erodes deterrence but reduces confidence in the security guarantees that have kept our allies willing to live under our “nuclear umbrella” for more than seven decades.
The Folly of Limited Nuclear War
Global stability rests foremost on the likelihood that a direct, major great-power confrontation incurs a real risk of all-out nuclear war. Unsound theories that nuclear escalation can be contained increase the likelihood of a nuclear conflagration and jeopardize the lives of millions. Political and military leaders of nuclear states must be convinced that direct armed aggression against another nuclear power—or the allies covered by their nuclear umbrellas—is not an option. Even when the escalatory risks appear low, the leaders of nuclear weapon states must take pause knowing the catastrophic nuclear consequences of getting it wrong.
To effectively deter all uses of nuclear weapons, potential belligerents must believe and fear that the United States would massively retaliate by using a force disproportionate to the size of their attack. Despite the NPR’s claim that new weapons will not enable “nuclear warfighting,” the idea that belligerents could exchange low-yield nuclear weapons with the “objective of limiting damage if deterrence fails” is the tacit acknowledgment that the United States is making plans to engage in limited nuclear wars.
Unsettling Our Allies
America’s allies are unsettled by an NPR that envisions battlefield nukes that would most assuredly be exploded on someone else’s homeland—potentially theirs. The U.S. nuclear umbrella rests with the assurance that an attack on ally constitutes an attack on the United States itself. The idea that the U.S. forces would engage in a limited nuclear exchange to avoid risking attacks on American cities is the surest way to undo the nuclear nonproliferation protocols accepted by U.S. allies.
Recall that the French withdrawal from NATO in 1966 was predicated on its lack of confidence in Washington’s nuclear security guarantee. French President Charles de Gaulle was convinced that in the event of a Soviet attack, the United States would not risk Washington and New York to save Bonn or Paris. The U.S. policy of flexible response reinforced these misgivings. Under this policy, the United States would respond in steps to Soviet aggression, first with conventional forces, then short-range nuclear weapons against troops on the battlefield in Europe, and finally—and only if necessary—long-range missile strikes aimed at Moscow and other Soviet cities. Upon withdrawal from NATO, De Gaulle issued a clear warning that any invasion that threatened France would evoke an all-out French nuclear strike on the belligerents.
That is why the new NPR’s focus on a flexible, tailored response has been met by steep criticism by U.S. allies in Europe. Germany’s Foreign Minister Sigmar Gabriel, for instance, explained that “the U.S. Administration’s decision to develop new tactical nuclear weapons shows that the spiral of a new nuclear arms race has already been set in motion. As at the time of the Cold War, we in Europe are particularly at risk.” By doubling down on the tailored, flexible response policy, the NPR plays right into China’s and Russia’s hands. It undermines our security guarantees and delegitimizes U.S. nuclear deterrence. Allies who lack confidence in U.S. extended deterrence will have no choice but to either bow to Chinese and Russian coercive influence or develop their own strategic arsenals.
Effective deterrence requires U.S. nuclear strategy to draw the clearest possible line between requisite levels of aggression and the invocation of nuclear defense of the United States and our allies. By developing low-yield weapons and expanding our policy for their use, we are signaling our willingness to fight a full-scale great power or limited nuclear war. This risks severe miscalculation by undermining the certainty that massive conventional or low-yield nuclear attacks will quickly escalate into a calamitous nuclear exchange. It is important for U.S. policymakers to heed Former Deputy Defense Secretary Robert Work warning that, “Anyone who thinks that they can control escalation through the use of nuclear weapons is literally playing with fire. Escalation is escalation, and nuclear use would be the ultimate escalation.”
This legitimate fear of nuclear escalation drives great power restraint. Deterrence is severely weakened by an NPR that raises the threshold for nuclear calamity and encourages China and Russia to prepare to fight wars that are intended to remain below the threshold for massive nuclear retaliation.
We cannot forget that a strong, credible nuclear deterrent force is—first and foremost—the ultimate protection against a nuclear attack on the United States, the one existential threat to the survival of our nation. In addition, it underpins the opportunity for the peace and prosperity of our allies, partners, and friends. It shapes great power competition by severely constraining the probability of direct armed conflict amongst nuclear weapons states. Our nation’s leaders must think twice before funding new types of nuclear weapons that erode our nuclear deterrent, undermine our nuclear alliances, and raise the likelihood of great power wars that can quickly escalate into nuclear devastation.
Captain Adams retired from the Navy in 2016 after 31 years of service. He commanded Provincial Reconstruction Team Khost, the USS Santa Fe (SSN-763), and the USS Georgia (SSGN-729B).
 Office of the Secretary of Defense, “Nuclear Posture Review 2018,” media.defense.gov/2018/Feb/02/2001872886/-1/-1/1/2018-NUCLEAR-POSTURE-REVIEW-FINAL-REPORT.PDF
 Drew Middleton, “The De Gualle Nuclear Doctrine is Alive in Paris,” New York Times, 5 May 1981, www.nytimes.com/1981/05/06/world/the-de-gaulle-nuclear-doctrine-is-alive-in-paris-military-analysis.html
 Foreign Minister Sigmar Gabriel, “Press Release On the Publication of the US Nuclear Posture Review,” 3 February 2018, www.auswaertiges-amt.de/en/Newsroom/bm-veroeffentlichung-us-nuklearstrategie/1433732.
 Statement of Robert Work, Deputy Secretary if Defense, 25 June 2015, docs.house.gov/meetings/AS/AS00/20150625/103669/HHRG-114-AS00-Wstate-WorkR-20150625.pdf