It’s a question best answered in the first instance by posing another question. Do you believe we should have the capacity to defend our island continent from attack by other nation-states? For me, that is an easy question. The answer is yes.

We hope the need never arises. We like to think our community of nations has matured. But a smart country will insure against the unlikely in the same way we insure against our house burning down. The event is unlikely but the consequences of not being prepared are too awful to contemplate.

So unlikely as it is that we might be invaded, an insurance policy is sensible. Australia insures itself in many ways. It engages in international diplomacy and backs a rules-based system in international forums for dealing with aggressive intentions. It also does everything it can to insure against the failure of that diplomatic and legal framework. In turn, it embraces a military posture which focuses in the first instance, on a preference to defend ourselves independently from external attack. We also look to alliance relationships to strengthen our defences.

Submarines are arguably the most important platform in our defence kit. Their near invisibility and capacity to surprise remain important. From their undetected positions, they can launch both short and long-range weapons. It’s been suggested that surely we don’t need subs when we now have drones. No, drones aren’t stealthy, can’t carry heavy weapons, have limited range, and can’t pre-position without the aid of a relatively easily detectable surface ship.

It’s the world’s worst kept secret that submarines play an intelligence role. They can spend months getting close up and personal with the enemy or potential enemy. Every country serious about protecting themselves still has them. For good reason.