With the May 3 election campaign degenerating into a cost-of-living auction, Peter Dutton’s promise of a $21 billion, five-year increase in defence spending is a much-needed recognition of the increasingly dire strategic outlook Australia is confronting.

Outside the nuclear energy policy, it is the Coalition’s single biggest promise of the campaign thus far, dwarfing the 25¢ cut to fuel excise ($6 billion) or cost of living tax offset ($10 billion), or matching of Labor on Medicare bulk billing incentives ($9 billion).