We are in a dangerous new nuclear age, according to a growing number of world leaders. The signs are not just in Russia’s threats to use its nuclear arsenal, or China’s steady build-up of its nuclear capabilities.

The signs are also plain to see in a single sentence, buried in an otherwise dull strategic document, released last month by the Trump administration.

Today, international and political editor Peter Hartcher on Donald Trump’s nuclear ambitions. And why Australia must begin thinking about acquiring its own nuclear weapons.