During Britain's recent parliamentary elections, Liberal Democrat leader Nick Clegg argued that the U.K. should scrap the proposed "like-for-like" replacement of its submarine-based nuclear deterrent, known as Trident, with a similar modernized system. As a possible alternative, Clegg's party has suggested fitting Britain's Astute-class submarines with nuclear cruise missiles, or in the event of a crisis, arming these same submarines with Trident missiles. Although such proposals may lead to financial savings, they are deeply flawed and could have far-reaching strategic and political implications for both the United Kingdom and its NATO allies. With Clegg now part of Prime Minister David Cameron's coalition government, he will hopefully "get real" about Trident, as former Prime Minister Gordon Brown urged in the second prime ministerial debate on April 22.
Rather than enhancing U.K. and NATO security, the arming of submarines with nuclear missiles during crises is potentially destabilizing, since it could provoke an adversary to increase their own state of readiness. By contrast, continuous at-sea deterrent patrols virtually eliminate the risk of sending inadvertent escalation signals. Even if the nuclear-armed submarines may never be called upon, they provide a hedge against unforeseen threats while minimizing the risk of crisis escalation.
It is also debatable whether a system based on cruise missiles will provide an adequate deterrent. The range of a cruise missile is up to 1,550 miles, in comparison to a Trident D-5 ballistic missile, whose range is over 4350 miles. This means that in order for a submarine armed with cruise missiles to carry out an effective strike, it must be closer to its target, making it more susceptible to attack. Cruise missiles are also more likely to be shot down if detected. Given these factors, such a weapon system will only add limited value to NATO's defense posture. Furthermore, the merit of maintaining a nuclear weapons platform that only has limited deterrence capability should be heavily scrutinized.