Moderation isn't sexy, particularly when it comes to nuclear weapons. But balance is exactly what is missing from contemporary nuclear debates. In his recent book, The Case for US Nuclear Weapons in the 21st Century, Brad Roberts makes a nuanced argument that, while disarmament is the long-term objective, nuclear weapons remain crucial to US security and for too long they have been neglected.

According to Roberts, America's adversaries 'may believe that they can engage in nuclear coercion and blackmail and that, in extremis, they could resort to nuclear employment'. This argument is likely to see Roberts placed in the pro-deterrence camp which opposes nuclear disarmament, which both proves a point and is also a shame: disarmament advocates and deterrence believers are talking past each other, to their mutual detriment.

For experts, Roberts' book offers a thoughtful, straightforward approach to today's nuclear challenges. It will also provide insights to those wanting a deeper understanding of the role of nuclear weapons in US policy, particularly as an extended nuclear deterrence guarantee to US allies in Europe and Asia.

The Case for Nuclear Weapons provides at least three important contributions to nuclear debates. First, in the course of making the case for US nuclear weapons, Roberts imparts first-hand experience about the nuclear policy-making process from his time working on the US Department of Defense's 2010 Nuclear Posture Review. This discussion includes the increasing influence and salience of US allies in nuclear decision-making.

Second, while many arguments in favour of maintaining and modernising nuclear weapons focus on their 'enduring value as insurance against the return of major power war', Roberts instead focuses on the intellectual gap in considering what happens if deterrence fails. What if a seemingly irrational adversary believes that in extreme circumstances the use of nuclear weapons would serve their interests? What if they believe they can use nuclear weapons against the US and not only survive, but also win the war? This is not a completely new argument, but it has been largely missing from nuclear debates.

Lastly, Roberts offers a warning about the state of the US arsenal after decades of neglect in investment and thinking, manifest in a series of recent mishaps involving US nuclear infrastructure. Deterrence relies on credibility, and this requires investment in the arsenal.

But neither of these last two points, nor Roberts' first-hand experience in policy-making, should put his argument squarely in the anti-disarmament camp. In the book's conclusion, the tone shifts from focusing on adversaries' 'theories of victory' to calling for a 'balanced approach' in nuclear debates. This would combine 'political efforts to reduce and ultimately eliminate threats with military efforts to deter existing threats', as argued in the 2009 Strategic Posture Commission report. Indeed, the US is committed to 'twin projects' to adapt nuclear deterrence to 21st century threats whilst reducing the role of nuclear weapons.

Such a balanced approach is noticeably absent in nuclear weapons debates at present, as evidenced by recent commentary over the North Korean nuclear test. While disarmament activists seized the opportunity to unfairly liken the Hermit Kingdom's nuclear program to the UK's Trident nuclear deterrent, those who believe nuclear weapons remain relevant are less vocal and tend to limit themselves to policy circles. Roberts calls this polarisation an 'advocacy mismatch.' Pragmatic debates are non-existent.

What then, is the way ahead for bridging the gap between disarmament and deterrence? First, strategic patience on the part of those who want to see faster disarmament. Second, and related, Russia must be a partner in further reductions. The belief by some disarmament advocates that unilateral steps by the US will prompt others to disarm is not realistic; according to Roberts, 'Recent history is unkind to this hypothesis.' And lastly, real progress will be made towards disarmament by examining the security reasons underpinning nuclear possession and reliance. This is a role specifically for the US as a leader for creating 'the conditions of peace and justice that would make nuclear abolition possible.'

Advocates for nuclear disarmament cannot ignore deterrence arguments, but neither can the policy community ignore the impatience and frustration among non-nuclear states with the lack of progress towards disarmament. There may be a case for US nuclear weapons at present, but that does not rule out disarmament as a long-term objective. Moderation in nuclear debates might not be sexy, but extremism is ugly.