Most history is hierarchical: it's about emperors, presidents, prime ministers and field marshals. It's about states, armies and corporations. It's about orders from on high. Even history "from below" is often about trade unions and workers' parties. But what if that's simply because hierarchical institutions create the archives that historians rely on? What if we are missing the informal, less well documented social networks that are the true sources of power and drivers of change?

A dangerous disconnect is emerging between the horrific impacts of even the limited use of nuclear weapons, and leaders and policymakers who seem intent on threatening nuclear use in an ever-expanding range of scenarios. If this continues, the risk that a nuclear weapon will be used for the first time in more than 70 years — deliberately or otherwise — will grow. We must return to a more sober dialogue and approach to policy.