Illustration: Matt Davidson Continental powers such as Napoleonic France, Prussia and the Soviet Union have tended to be landlocked and reliant on large standing armies, which have, of necessity been funded through arbitrary taxation and levies. British naval historian Peter Padfield has written a superb trilogy describing this phenomenon. The final in that series, Maritime Dominion – And the Triumph of the Free World, speculates that the global balance is shifting away from the West. The publication of the latest United States National Security Strategy supports rather than rebuts Padfield's bleak prediction. Ever since the Union Jack was raised at Botany Bay, Australia's fate has been inextricably tied to the fate of the dominant maritime power of the day. We have truly been a lucky country as global maritime supremacy passed peacefully from Britain to the United States. Our crucial sea-lanes, and free access to the global commons, which now includes space and cyber-space, has been guaranteed by the forces of benign foreign powers whose values we share. We are net importers of security funded by others. That is why shifts in America's strategic posture matter to Australia.

The US and Philippines engage in exercises near the contested Scarborough Shoal in waters off of the Philippines on January 20. Credit:BULLIT MARQUEZ That status quo has endured since I enlisted in the Australian Army in 1974. Indeed like most of our political and strategic leadership I have accepted that position as immutable, confident in the belief that no despotic power will ever ultimately triumph over the West, with our open, innovative societies and vibrant capacity to adapt to challenges. No authoritarian, continental power has ever defied this apparent iron law of history that has granted supremacy to maritime powers. A Chinese H-6K bomber patrols islands and reefs in the South China Sea in 2017. Credit:Liu Rui I am no longer so confident.

In his recent Quarterly Essay, Hugh White has made a persuasive case that America is now in full retreat from our region of vital security concern. I sadly think he is correct. HMAS Kanimbla arrives in Sumatra, Indonesia, in 2009. Credit:Andrew Dakin The latest US National Security Statement confirms this, despite its enthusiastic reception by many local commentators. While its assertive rhetoric commits it to defeating national threats and names China and Russia as hostile powers, it is not backed by a credible force structure. In particular, American power is waning where it matters most to Australia, in the area bordering our ASEAN neighbours, who are vulnerable to Chinese coercion. Rather than a military pivot we have reassuring rhetoric from Washington about a strategic recalibration to fight conventional state adversaries, rather than terrorism. From Canberra we have the usual boilerplate and wishful thinking, with the exception of Julie Bishop, though I think she underestimates the potential threat of Russia in the cyber domain. More importantly, China differs from previous autocratic continental powers that failed to achieve global hegemony: it has a massive coastline of 14,000 kilometres , which accommodates superb deep-water ports. It also shares land borders with weak or compliant states like Pakistan, Thailand and Burma. And it faces no serious peripheral foes, which proved the bane of Prussia, Nazi Germany and the Soviet Union.

While the United States remains the world's foremost military power, it is over extended and depleted by long wars in the Middle East and South East Asia. Its nuclear missile forces are old to the point of obsolescence, requiring massive capital investment and modernisation. Its air force, crucial to global power projection, is comprised of ageing airframes at historically low levels of combat readiness. When Republicans froze expenditure under Barack Obama, this seriously curtailed overdue investment in US air power. The ground reality in the South China Sea has altered irrevocably. Freedom of navigation exercises performed by the US are empty gestures. The Americans will not risk a nuclear exchange over the Paracels or even Taiwan. That vindicates China's long-term investment in its land-based missile system, termed Anti Access-Area Denial. It developed this strategy in response to its humiliation during the Taiwan Gulf crisis of 1996, when two American carriers arrived undetected in the Taiwan Straits. Loading Australia sleepwalks into this new era mouthing platitudes about not choosing between our trading and security partners. Both China and America will soon demand a choice. That will make our culture war about Australia Day pale into insignificance. Some form of conflict in our region seems inevitable to me.

The era when Britannia ruled the waves is over. So indeed is the era of the maritime supremacy of the West. We may eventually be nostalgic for it.