United Kingdom Debates Scrapping Nuclear Program: Why the United States Cares
The United Kingdom has maintained a continuous at-sea nuclear deterrent since April 1969, with one ballistic missile submarine on patrol at all times. The David Cameron government reinforced its commitment to maintaining its nuclear posture in the November 2015 Strategic Defence and Security Review (SDSR). Yet, with Parliament likely to vote in the fall on whether to replace the current fleet of Vanguard-class submarines, discussion about the future of the UK nuclear arsenal has reached fever pitch. This vote will follow the country’s referendum on its continued membership in a reformed European Union, fueling concerns that the United Kingdom’s role as a global player is rapidly diminishing.
Since being elected the Labour Party leader in May 2015, antinuclear activist Jeremy Corbyn has maintained his long-held opposition to the use of nuclear weapons. To continue to drum up public support for his stance, Corbyn will speak at a protest in London’s Trafalgar Square on February 27. The Scottish National Party, which holds 56 seats in Parliament, also supports Corbyn and could join his efforts to block budget resources to modernize Trident. Estimates to build four new strategic ballistic missile submarines—dubbed “Successor-class”—have increased from £26 billion to £31 billion since 2006, with another £10 billion in contingency spending. Other critics of Trident have cited the rising cost and question the relevance of a traditional nuclear deterrence in the face of modern-day threats like al Qaeda or ISIS. Several Labour members of Parliament, union members, and the Cameron government, however, continue to stand behind modernization.
While it seems likely Britain will retain its nuclear deterrent, the debate could have critical implications for global security, as noted recently by U.S. secretary of defense Ash Carter.
Q1: Why is this issue important to the United States?
A1: There are only two nuclear guarantors of NATO’s security: the United States and the United Kingdom. France’s nuclear deterrent contributes to alliance solidarity, but its nuclear forces are not committed to the alliance, nor are they included in alliance planning. If the United Kingdom were to give up its deterrent, that would leave the United Sates as the sole nuclear guarantor for the alliance. This would have two consequences. First, there would no longer be two centers of decisionmaking. Under the current construct, potential adversaries are deterred by the fact that it is unlikely that both nuclear-armed NATO states would fail to respond to aggression. Removing British nuclear weapons would significantly weaken this deterrent. Second, the United States would bear the sole political burden of NATO’s nuclear deterrence, a singularity Washington policymakers have sought to avoid for decades.
In a broader context, the United States stands with only four other countries as acknowledged and legitimized possessors of nuclear weapons—Russia, China, France, and the United Kingdom, who are likewise the permanent members of the UN Security Council. This position is enshrined in the Nuclear Non-Proliferation Treaty and reflected in their role at the United Nations. Within the world’s five acknowledged nuclear weapons states, only the United States, United Kingdom, and France share common values, strategic interests, as well as a common sense of responsibility for global peace and security. For decades, the United States and United Kingdom, along with France, have stood side-by-side as responsible, like-minded, Western stewards of nuclear weapons and as allies and partners on the broader geopolitical stage. To step away from its nuclear role, unilaterally and without any broader negotiated arms reductions, will inevitably reduce the United Kingdom’s role and leadership within the United Nations, NATO, and the broader international security apparatus and leave the United States to assume greater responsibility on its own in that sphere as well.
Q2: How might a choice by the United Kingdom to forgo its nuclear weapons impact its relationship with the United States?
A2: Collaboration and partnership in the nuclear weapons arena, especially between our naval components, is a cornerstone of the U.S.-UK military and intelligence-sharing relationship. Shared roles as nuclear weapons states serves as a strategic equalizer between the United States and the United Kingdom, while at the same time drawing the countries close together on the most consequential of security threats. This close partnership goes all the way back to the 1958 U.S.-UK Mutual Defense Agreement and the 1963 Polaris Sales Agreement and is reflected in joint development efforts on the missile compartment to be used on both the U.S. Ohio-class (SSBN) replacement program submarines and on the Successor boats. The countries speak the same language, share many of the same concepts and approaches, and even use the same technology. The nuclear partnership is an important part of what makes the U.S.-UK relationship special, and to remove it would inevitably make the relationship less so.
Q3: The UK arsenal is very small, just over 120 strategic weapons (and a total stockpile of 225 weapons), deployed on a single delivery system of four Vanguard-class submarines. Why does it make a difference?
A3: The UK nuclear force is relatively small, but that does not mean it is either militarily or politically irrelevant. Far from it. In NATO, the United States and the United Kingdom share operational responsibilities through theformal commitment of our nuclear forces to the defense of the alliance. NATO’s 2014 Newport Summit Statement says: “The strategic nuclear forces of the Alliance, particularly those of the United States, are the supreme guarantee of the security of the Allies. The independent strategic nuclear forces of the United Kingdom and France have a deterrent role of their own and contribute to the overall deterrence and security of the Alliance.”
While France is not part of the NATO’s Nuclear Policy Group, French president Hollande has stated that France would treat a threat against the survival of a European ally as a threat to its vital interests.
But, as noted above, if the United Kingdom withdraws its nuclear forces, the United States alone would be responsible for NATO’s nuclear deterrent. The political and military impacts of such a step would be profound—placing the full burden of extended deterrence solely on the shoulders of the United States. From both NATO’s and the United Kingdom’s defense perspective, this may be of even greater importance given recent Russian military aggression and its ongoing extensive nuclear force modernization. Russian submarines have been sighted in the North Sea and North Atlantic, and Vice Admiral Clive Johnstone of NATO stated this month that there is now more “activity from Russian submarines than we’ve seen since the days of the Cold War.” Unfortunately, previous British defense spending cuts eliminated the UK maritime patrol aircraft making it difficult for the United Kingdom to detect Russian submarine activity.
The UK nuclear force is critical on a bilateral basis as well. The United States retains a triad of nuclear weapons delivery systems—land, air, and sea—but our submarine-based sea leg is the most survivable and flexible nuclear component, and it carries a disproportionate burden of our overall deterrent. The Royal Navy keeps three submarines in operation at any one time. That may not sound like much, but keep in mind that the United States only keeps 11 boats in continuous operation. Moreover, we use the same missiles and collaborate closely in our nuclear deterrence operational missions. The loss of the UK submarine-based nuclear deterrent would force the United States to absorb substantial deterrence risk that today it shares with our closest bilateral partner.
Q4: One less nuclear-armed state in the world. Couldn’t some suggest that a decision by the British government that it no longer needs its nuclear weapons represents an enormous win for the nonproliferation regime and opens the door to further nuclear reductions by other nuclear-armed states?
A4: The five recognized nuclear weapons states share a burden and responsibility to pursue nuclear disarmament as called for by Article VI of the Nuclear Non-Proliferation Treaty, but meaningful disarmament requires true multilateral negotiations and reductions that involve reducing nuclear threats and burdens to all nations—allies and adversaries alike. A move by the United Kingdom to unilaterally disarm now, without securing any reductions from potential nuclear adversaries, simply shifts its deterrence burden to its allies, the United States and France, while eliminating negotiating leverage—or even a seat at the table—for any future arms-control efforts. It is worth noting that the United Kingdom, alone among nuclear weapons states, has probably made the sharpest cuts over the past two decades in its nuclear arsenal. It has gone from two systems—an air-delivered bomb and a submarine-launched ballistic missile (SLBM)—to just one, and it has similarly made major reductions in its overall nuclear warhead stockpile and its number of deployed weapons.
Rebecca Hersman is director of the Project on Nuclear Issues and senior adviser with the International Security Program at the Center for Strategic and International Studies (CSIS) in Washington, D.C.
Critical Questions is produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).
© 2016 by the Center for Strategic and International Studies. All rights reserved.