In a speech some months ago on the government’s 2020 Defence Strategic Update, Prime Minister Morrison said the “period of the 1930s has been something I have been revisiting on a very regular basis”. He explained that when we “connect both the economic challenges and the global uncertainty, it can be very haunting”. Australia faced an “existential threat” as the “global and regional order collapsed”. Morrison was probably trying to scare us a little—to soften up the public for some potentially tough times and tough decisions, including with respect to defence spending. Nevertheless, it is worth reviewing the history of…