Britain Weighs the Need for Nuclear Deterrence

I just attended an interesting discussion at the Brookings Institute on the future of Britain’s nuclear deterrent force.

In the final years of the Cold War, Britain maintained a variety of nuclear warhead delivery systems including submarine-launched missiles, air-dropped bombs, heavy artillery, and short range missiles. Beginning in 1991, Britain began to retire most of these systems. By 1998, Britain’s nuclear capability relied solely upon a continuous at-sea deterrent (CASD) force of four Vanguard-class submarines armed with Trident sea-launched nuclear ballistic missiles.

These four submarines take turns patrolling at sea so that anyone who would contemplate using a nuclear weapon on British soil (probably destroying all submarines in port) would have to weigh the cost of a retaliatory nuclear strike launched from the submarine patrolling safely at sea. It’s a brilliant way to maintain continuous nuclear deterrence as cheaply as possible.

However, this brilliance hasn’t protected Britain from the kind of kick-the-expensive-can-down-the-road conundrum that democracies are made of. Britain’s entire nuclear infrastructure now revolves around the Trident missile as a delivery system. The last Trident-capable Vanguard submarine is set to retire in 2028. However, development of an alternative to the Trident system (for example, a land-based ballistic missile system) could not be completed before 2040 at best.

This capability gap is the context in which Britain’s coalition government published a review of the CASD principle earlier this year. The review found it prohibitively expensive in both time and money to retool the Trident-based nuclear force for alternative delivery systems. The review concluded that it would be far simpler to simply reduce the Vanguard fleet’s at-sea posture to less than continuous while transitioning to two Successor-class submarines that can carry the Trident until a replacement delivery system could hope to be developed.

The Liberal Democratic Party, enjoined with the Conservative Party in Britain’s coalition government, is now proposing that Britain cease the continuous patrolling for one of four non-continuous options. Of these, the Liberal Democratic Party is promoting a policy of “focused deterrence,” in which patrolling would continue on a regular but non-continuous basis while maintaining the capability to return to continuous patrolling for the duration of a (hopefully) short crisis.

The Liberal Democrats frame “focused deterrence” as a shedding of Britain’s last Cold War-era holdover.  This idea has its merit although the impending capability gap, not the end of the Cold War, was the impetus for the review that suggested “focused deterrence” as a stopgap measure.

The principle question grappled with during today’s discussion was on the risks and benefits of ceasing the continuous patrolling posture. Once the Vanguard submarines begin taking breaks between patrols, the automatic guarantee of retaliation for a nuclear attack on Britain is gone. We’re then left to consider the likelihood of various nuclear scenarios including crises that may spiral into nuclear escalation against the initial desires of all parties. Perversely, the reintroduction of a homeported submarine to the open sea could serve as an escalating factor if such a crisis began during one of the breaks in patrolling.

Ultimately, Britain has to decide whether to risk a highly unlikely, but not impossible, nuclear attack in an era of relative peace between states. Ours being an imperfect world, all available options carry some level of risk that Britain will have to live with.

Offhand, this is an interesting question for probabilistic cost/benefit analysis: What is the projected cost of a nuclear attack on Britain multiplied by the likelihood of that attack? The monetized cost of any successful nuclear attack is obviously very high, but when we multiply this cost by the likelihood of its occurrence, we’re looking at a much smaller figure (though some analysts caution that the logic of probabilistic cost/benefit analysis may break down at the extreme where catastrophic-level events are too rare to accurately measure their probability or cost).

Multiplying potential costs by the probability of their realization is necessary to avoid bankrupting the treasury in preparation for every imaginable contingency as the defense-industrial-congressional complex would have us do.  John Mueller and Mark Stewart used this technique to show that the United States would have to prevent a guaranteed (i.e., 100% likelihood of occurrence) 9/11-scale attack every year to break even on its extravagant counterterrorism spending since September 11, 2001. Britain’s current challenge is in the far less obvious midzone where some subset of reasonable constituents are prone to disappointment whether Britain continues with CASD or not.

Britain's break-even analysis should not look like this. Credit: Mueller and Stewart, 2011

Britain’s break-even analysis should not look like this.
Credit: Mueller and Stewart, 2011

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: