A tomahawk cruise missile launches from the Arleigh Burke-class guided-missile destroyer USS Shoup (DDG 86) for a live-fire exercise during Valiant Shield 2018.(Navy/ William Collins III)

It may seem counterintuitive that America investing in a new nuclear weapon design could help lower the chances of a nuclear conflict. But in this new op-ed, Naval War College professor David A. Cooper argues just that, noting that the concept for a new sea-launched cruise missile could end up benefitting nonproliferation and arms control efforts. 

A simmering debate over the fate of the new intermediate-range nuclear-armed sea-launched cruise missile (SLCM-N), initiated by the Trump administration, has centered on whether the weapon is needed to strengthen deterrence in the face of escalating geostrategic competition with China and Russia. Because then-candidate Joe Biden rejected this argument, his administration’s recent decision to seek funding for the program took many by surprise, disappointing opponents and giving supporters new hope.

Both sides of the debate share a common understanding that SLCM-N would bolster US nuclear “warfighting” capabilities in Asia and other regional theaters—offering a shorter-range and lower-yield nuclear option than intercontinental-range strategic systems intended primarily to deter a full-scale nuclear war. Where they differ sharply is about the implications.

Opponents argue that the existing US nuclear arsenal is more than sufficient to deter Chinese or Russian aggression and, more importantly, that introducing new regional nuclear warfighting capabilities increases the risk of nuclear war by lowering the threshold for nuclear use — meaning that the United States would be more willing to use locally deployed, lower-yield, and shorter-range nuclear cruise missiles. There are also concerns that an adversary would not know whether inbound cruise missiles were armed with conventional or nuclear warheads, thus increasing the risks of miscalculation, a situation that already applies to Chinese and Russian deployments of dual-capable missiles.

Supporters, by contrast, contend that failing to counter Russia and China’s deployments of sub-strategic nuclear systems could invite military adventurism if either country believes that this offers a military advantage over the United States that opens the door for conventional aggression or nuclear coercion against vulnerable American allies and friends.

In a nutshell, opponents assert that arming US naval forces with more usable nuclear warfighting systems increases the risk of starting a nuclear war, whereas proponents assert that the best way to avoid a nuclear war is for the United States to demonstrate that it is prepared to fight one at every level of conflict. These differences reflect a longstanding debate about the role, value, and workings of nuclear deterrence.

But too often overlooked in this debate are important arms control and nonproliferation considerations, which need to be factored in when discussing whether or not to move forward with the new system. The reality is that the SLCM-N offers an opportunity for arms control advocates in the US government to leverage new capabilities and, potentially, force Russia and China to new agreements.

The arms control case for SLCM-N boils down to achieving negotiating leverage. The United States does not currently possess any sub-strategic range nuclear missiles, whereas both China and Russia have deployed such forces. For example, in addition to deploying mobile land-based missiles in contravention of the now defunct Intermediate Nuclear Forces (INF) Treaty—which is what provoked the US withdrawal—Russian naval forces are armed with the nuclear-capable Kalibrits (SS-N-27) and President Vladimir Putin plans to augment these with a new generation of naval nuclear hypersonic missiles. Russia’s shorter-range nuclear forces also dwarf the small NATO arsenal of tactical nuclear gravity bombs.

China, meanwhile, has far and away the world’s largest arsenal of intermediate-range nuclear-capable missiles, which are arrayed against American allies and the US land and naval forces that are deployed to protect them. Under these circumstances it is not surprising that Moscow steadfastly refuses to discuss arms control measures for any sub-strategic nuclear forces and seems disinclined to negotiate new reductions in strategic nuclear forces in which it now enjoys a numerical advantage. And Beijing refuses to countenance participating in any arms control whatsoever as it continues to build up its nuclear forces across the board. In sum, neither seems to have much incentive to bargain away their current advantages or future prospects.

Moving forward with the SLCM-N could force Moscow and Beijing to rethink their resistance to new arms control negotiations, especially for sub-strategic systems. The Trump administration had made this point explicitly. As one senior Defense Department official noted, “We have opened the door to future arms control discussions with Russia by stating that we would consider forgoing development of the nuclear sea-launched cruise missile if Russia is willing to engage in meaningful discussion of non-strategic nuclear arms control.”

A nuclear cruise missile could change the thinking of Russia and China.

The scope of US naval deployments in Asia and Europe would make SLCM-N a potent counterbalance to existing Chinese and Russian sub-strategic nuclear forces, offering real negotiating leverage for the first time in years – assuming Beijing and Moscow are convinced that Washington is serious and has the political will to follow through.

The idea of trying to “arms race toward arms control” may seem counterintuitive. However, this “two track” approach—promising to develop and deploy new systems to counter a competitor’s existing deployments, while at the same time offering to negotiate less costly and volatile alternatives—was a bipartisan tactic that enabled the Carter and Reagan administrations to navigate the long and bumpy road leading to the INF and START treaties. Put simply, trying to negotiate arms control from a position of weakness is unlikely to succeed. The only disarmament on offer in such circumstances is usually unilateral, which is apt to embolden competitors and alarm allies.

The nonproliferation case for SLCM-N boils down to preserving allies’ confidence that they can rely on American extended deterrence guarantees without the need to obtain their own nuclear weapons. This represents the other side of the deterrence coin: assurance. Allied confidence in the American “nuclear umbrella” is an underappreciated element of the durable success of the Nuclear Nonproliferation Treaty (NPT). When John F. Kennedy predicted in 1960 that up to twenty countries could have nuclear weapons in a few years, many of the countries that were contemplating going nuclear at the time were US allies. A key reason this did not happen is that Washington convinced them that extended deterrence was a reliable alternative.

Unfortunately, allied confidence in extended deterrence has been badly shaken over the past decade, first by President Obama’s open doubts about the role of nuclear weapons, and then by President Trump’s open doubts about the role of alliances. The incalculable damage now being done to allied perceptions of US reliability by President Biden’s Afghanistan withdrawal fiasco can only feed these seeds of doubt. Therefore, convincing allies that they are still safe under the shelter of an American nuclear umbrella may be one of the most critical requirements for ensuring the long-term viability of the NPT.

We have seen in recent years once unimaginable domestic debates about the potential need to go nuclear by key allies, including Australia, Germany, Japan, South Korea, and Turkey. These are countries that, should they ever conclude that they do need to go nuclear, have the wherewithal to do so, and in some cases, like Japan, very quickly. While not a likely scenario, it is no longer unthinkable that the NPT could ultimately unravel due to an irreparable loss a confidence in extended deterrence by America’s allies.

The role that SLCM-N could play in assuring skittish allies about the credibility and resolve of American security guarantees thus could be a critical factor. In this context, the question of whether SLCM-N is really necessary for extended deterrence is, oddly, in some sense beside the point. To the extent that SLCM-N is perceived by allies like Japan as a concrete demonstration of America’s resolve and commitment to extended deterrence, then it is important for that reason alone.

Staying the course on SLCM-N will not by itself lead to new arms control talks or preserve nuclear nonproliferation. Cancelling it, however, is likely to undermine both of these worthy causes.

David A. Cooper is the James V. Forrestal Professor of National Security Affairs at the United States Naval War College in Newport, Rhode Island. He is a scholar-practitioner who previously served as a career official in the Office of the Secretary of Defense including as Director of Strategic Arms Control Policy and Director of Nonproliferation Policy. His most recent book is Arms Control for the Third Nuclear Age: Between Disarmament and Armageddon (Georgetown University Press, 2021). All views are his alone and do not reflect official positions.