This year, the Donald J. Trump administration will review the state of U.S. nuclear forces, the nation’s nuclear policy and posture, and how it fits the current and emerging strategic environment. With that review comes an opportunity to communicate to friends and adversaries alike that deterrence has returned to the top of the U.S. nuclear agenda. Communicating that priority should begin with the reaffirmation of commitment to modernizing the nuclear triad, as essential now for 21st century deterrence as it has ever been.
Nuclear deterrence is the foundation of U.S. security. Last fall, Secretary of Defense Ash Carter described it as “the highest priority mission of the Department of Defense.” Eight former commanders of U.S. Strategic Command have recently affirmed that “there is no higher national security priority than deterring the actual or coercive use of nuclear weapons against us and our allies.”
The U.S. deterrence posture has long maintained a triad, consisting of land-based ICBMs, sea-based ballistic missiles carried by nuclear submarines, and bombers carrying gravity bombs and air-launched cruise missiles. After the end of the Cold War, reductions in the role and numbers of nuclear weapons also resulted in an extended procurement holiday—indeed, too extended a holiday. As a result, today’s weapons and delivery systems are the oldest in U.S. history.
To sustain deterrence, the United States has in recent years embarked on a broad but necessary modernization plan to refresh all aspects of the aging enterprise, including new platforms and delivery systems, life-extended warheads, improved command and control, and refurbished facilities.
The path forward on modernization took shape early in the Obama administration, with its outlines hashed out with Congress and now largely accepted on a bipartisan basis. Keeping this effort on track will be a critical national security objective for the Trump administration and beyond.
Proliferation by countries like North Korea, for instance, introduces new challenges for deterrence. Recent events from Russia’s annexation of Crimea to China’s belligerent actions in the South China Sea demonstrate that hostile nations will continue to challenge the status quo in unpredictable ways. The 21st century nuclear arsenal must respond not only to the challenges of 2017 but also those of the future.
Some critics disagree with the necessity of maintaining a triad. This past year, for instance, much ink was spilled to advocate eliminating both ICBMs and the nuclear air-launched cruise missile. Both of these and the larger triad they support, however, remain critical for 21st century deterrence.
The Long-Range Standoff Weapon will replace the original Air-Launched Cruise Missile from the early 1980s with a more reliable and stealthy replacement. Far from being a provocative or destabilizing influence, however, the LRSO is not a first-strike weapon, and will provide a credible instrument to help deter limited, regional nuclear employment.
Like its predecessor, the LRSO will be in the first instance carried by the B-52 bomber, in service since the 1950s. While the United States intended to replace its B-52 fleet in the late 1980s with the B-2 bomber, only 20 were acquired and 1980s stealth technology is itself out of date. The Air Force has recently begun work on a new long-range bomber, the B-21 Raider.
Maintaining a modern and agile bomber force is essential to crisis stability. It is also the only strategic platform that can be forward deployed in a highly visible way, signaling U.S. resolve during a crisis to allies and adversaries alike. Bombers are also the only leg of the triad that can be recalled once launched. Furthermore, the decreased radar signature of the B-21 and its carriage of cruise missiles will sustain the bomber capabilities in the advanced air defense environment of the 21st century. The combination of both gravity bombs and cruise missiles aboard bombers significantly improves their flexibility and credibility, and complicates the air defense job of adversaries.
Since the bomber force was de-alerted and removed from daily patrols, the United States relies on its nuclear submarines and ICBMs to meet day-to-day requirements. In a sense, these are used every day to deter the sort of massive attacks that would have existential implications for the United States and global security.
Of these, the ICBM leg of the triad holds special value and does so at considerably less cost than the sea-based leg. The U.S. ICBM force consists of silo-based Minuteman III missiles first deployed in 1970. Some critics have variously criticized ICBMs as a vulnerable and thus a tempting target, or as destabilizing for the ability of at least some fraction of them to be launched more promptly than other platforms.
Such arguments do not appreciate how the geographically dispersed ICBMs greatly enhance deterrence and stability by raising the nuclear threshold and severely complicating an adversary’s ability to execute a disarming first strike. Although the silo locations are known, their number and dispersion creates a “missile sink” that would require an attacker to employ a significant portion of its own nuclear weapons to neutralize. The Minuteman fleet is itself nearing its life-span, and the Ground-based Strategic Deterrent program will bring both a replacement missile and more modern facilities which are cheaper and easier to maintain.
The third leg of the triad consists of submarine launched ballistic missiles currently carried by the Ohio-class nuclear submarine (SSBN). The sea-based leg is usually described as the most survivable leg of the nuclear triad, but its relative invisibility under the ocean should not be taken for granted. Under the New START treaty the U.S. will put up to 70 percent of its operationally deployed strategic weapons aboard SSBNs, but several submarines are in port at any given time and only a portion of the fleet is ever on station.
The idea of eliminating another leg and depending more heavily on SSBNs itself carries great risk. New developments in anti-submarine warfare enabling adversaries to target this high concentration of weapons could be highly disruptive. With the elimination of ICBMs or nuclear cruise missiles, for instance, adversaries could devote greater resources toward anti-submarine warfare.
The real choice that the United States faces today is not between modernizing or simply maintaining the current nuclear force. Such a step is necessary for the United States to remain a great power. The choice is rather between the sustainment of the deterrent through modernization or disarmament and lost capability through age and rust.
During his confirmation hearing, incoming Secretary of Defense James Mattis reaffirmed the “absolute priority” of the nuclear mission. In every practical sense, meeting that mission means continued commitment to modernizing the triad and the nuclear enterprise more broadly. The current modernization path exists for good reason, and it should be sustained.
