The changeover, or attempted changeover, from one dominate empire to the next, or to a non-empiric system (end of Rome), is typically violent and that violence can take many forms. The Napoleonic war, WW1 and WW2 were simply the latest in this ever-reliable font of conflict and they shared a specific shape. That shape was of a large, clear-cut war with formal battles in continental Europe (for applicability’s sake, assume a large continental mass) with a largely naval war in Asia for WW2. However, this is not the only shape Imperial switchover violence can be, the Roman decline’s violence was very different. It took the shape of continuous barbarian invasions on a small to medium scale, the successful barbarian invasions tended to have about 10-40,000 people with ¼-1/2 being warriors for two main reasons; one, no other growing major power existed (Parthia was on the decline) and two, the Roman’s strategic defence system could easily stop anything bigger (mostly by starvation) from the Barbarians. The current situation will likely resemble the roman empires decline somewhat, not due to starvation but nuclear weapons, to illustrate how this works think of the cold war. The USA and the USSR, unlike every other set of empires in existence, never fought any direct major wars against each over, not even petty wars, instead they fought in proxy conflicts (Afghanistan, Vietnam, Korea), Nukes stop direct high intensity conflicts and force low intensity proxy conflicts to be used instead. Note: low intensity conflicts can’t do anywhere near as much damage as high-intensity conflicts and take longer to achieve similar ends, along with limited geographic availability and spread which is why most governments throughout history prefer high intensity conflicts when they can and then use soft power.
On the first reason, there exists a massive difference between our current situation and Rome’s, their currently exist multiple rising and established major powers. The established powers include Russia, China, and potentially Germany and India, depending on how events play out. That is, they are already powerful states with the connections (Germany’s is the Euro) and strength of a major power. The rising powers Iran, Brazil, South Africa and an assortment of states that only require the right circumstances. The potential of Germany comes from the fact that it dominates Europe and while Europe will certainly be poorer than it is now, it will still be quite powerful and besides, Germany is in a much better situation to exploit N.America’s east coast than China is due to geography and culture. However there are two very important traits that further change the situation; one, the current and future decline of both modern military and political projection, two, the fact that there are now multiple power blocks instead of the previous experience of there only being two power blocks (Axis and Allies, USA vs USSR, Napoleon vs the coalitions etc)
The decline of modern military’s capabilities has arrived in several ways and to each branch, army, navy and airforce. Modern Western armies are losing the ability to control and conquer territory in the third and second world, compare when in 1941 Britain conquered Iraq with a single infantry division and it took six years before major problems appeared, to America’s recent failed attempt of simply controlling the country via local proxies. Due to high oil prices and economic troubles, navies are slowly losing the battle against piracy and are finding it harder to patrol trouble spots and police the sea-lanes (not long till privateers and/or armed merchantmen appear). And in 2006 Hezbollah managed to almost negate Israel’s airpower, look up Hezbollah nature reserve to see how well fortifications work against air power. The problem for the major powers is that modern mechanised militaries still rule open and high intensity conflicts and only powerful or highly resilient defensive measures can stop them, such as guerrilla warfare or heavily entrenched defenders. This means that they will need to keep a large fraction of their militaries as modern mechanized forces instead of changing to more other forms more effective at client state subjugation. Two of the likely adaptations to this are a rise in the use of Auxiliaries and mercenaries by the major powers and the increased use of soft power to support a local hegemony that can control the region militarily and politically in the imperial powers stead. Auxiliary and mercenary forces would be forces from outside the empires cores that complement its military and balance it out; similar to how Rome used Auxiliaries to balance out its legions.
The multiple power blocks and the inability for direct wars of conquest to be fought provide an interesting dynamic since no one state can gain complete dominance and any weakening of one front allows another power to act. Here’s an unlikely but potential scenario; China’s dominance of Africa is being undermined by both South Africa and Brazil (working separately) who want better access to Africa, so it responds by moving forces (military and economic) from the Asian and N.American theatres to Africa to counter their ambitions. The resulting almost century (remember soft power is slow) long conflict called the Great African crisis by future historians and involves mostly the economic and political manipulation of proxies, with some battles and open conflicts (such as the Zaire war where a South African force attempts to reach Sudan and must battle a Chinese army back up by Tanzania) between the powers, but most of the battles are fought by Africans either as wars or insurrections. India responds to the weakened state of China in Asia to use its strategic location along the sea-lanes of China to Africa to force concessions out of China, such as eliminating the support given to Maoist (or other) rebels. Lest its forces and access to in Africa be cut of from the homeland, where they would be useless in a second Sino-Indian war, China is forced to acquiesce, until the great African crisis is over and it can punish the arrogant Indians. Germany, with the hegemony of Europe and as the client of Russia, takes advantage of China’s weakened position in the Americas to spread its influence and begins a long and difficult takeover of the both central America and N.America’s west coast, bringing it into conflict with Brazil. Iran uses the chaos in Africa to take over the Horn of Africa and consolidate its middle-eastern holdings. Then there’s all the little (relative to the big ons, big to those involved) wars and regional powers that are either in the firing line or taking advantage of the situation. Going by the War Nerd; the Tutsi will probably get their Central African Empire, the Vietnamese will almost certainly try to conquer Indochina (drawing a response from China), Indonesia trying the same trick as India, and what about a new power in N.America attempting to retake the coast (either one or both). Now the scenario above is a dramatisation of what could actually happen, and the time scale could easily be centuries since they’d be mostly using soft power and I just wanted to illustrate the dynamics. Important detail; all the powers would be using indirect forces heavily and supplementing their military with Auxiliaries (especially local forces) and mercenaries.
Why is all this important for Australia? Because Australia’s historical relationship with the dominant Imperial power has a fairly mercenary aspect. Australia has always exchanged military forces and a close alliance so that the dominant naval power, Britain once and now America, would protect our sea-lanes, not because of any ideological or moral reasons (though historical and cultural factors have helped). As it stands the military aid Australia has given has been of a high quality; in WW2 the Germans considered the Australian (and other colonial forces) to be the elite of the British army and there’s a quote from a Viet Kong commander that amounts to the same. Now that no power is likely to control the sea anywhere near as completely as the British did or America does now in the near future, an interesting choice will soon confront Australia. Since the agreement can’t exist and Australia will lose most of the wealth conferred by the sea-lanes no matter what agreements are made, Australia can either choose to disband most of its army and only keep enough to defend Australia while suffering the economic damage this brings. Or it can choose to continue with the current practice of exchanging military forces for wealth and sea lane protection and begin recruiting and sending out essentially mercenary brigades, both options have their pros and cons.
Downsizing the military would immediately free up resources that could be put to other ends, further the process of isolating Australia from the world, insure the safety of our soldiers and no blowback would occur from our forces being in a war somewhere. However, it does leave Australia more vulnerable since while Australia is in a phenomenal defensive position, it only matters when there are soldiers to back it up and this option could leave Australia without any forces with combat experience, also it lacks what can be a useful social valve and a replacement would be needed (currently it’s sport) and it involves greater economic damage and most likely greater loss of trade/resources. Keeping the current arrangement and instead working for multiple powers however allows Australia to gain wealth from the outside world, via both contracts/deals and old fashioned looting, make Australia an impenetrable fortress (Awesome defensive situation and experienced soldiers) and slow the isolation of Australia from the world. Blowback could occur (think terrorist attacks), there will be deaths, in the 1000 to 10,000s, potentially every year or decade and it requires an investment in the Australian military from a diminished pool of capital. The deciding factors will be recent experiences (does China push us hard to ally with it), dominant values and the perception of the problems facing the world. It’ll be an interesting time.
The defensive militaries structure would most likely be infantry based and rely on an increase in either the reserve or the beginning of militias, with fixed defensive points on strategic locations and limited support in the form of tanks, artillery and airforce and a navy focussed on sea denial tactics and anti-piracy operations. Even if the mercenary route is chosen that defensive army is likely to exist. The mercenary military structure would be based around elite infantry, limited quantity means quality needs to be higher, with attached armour and artillery divisions (won’t be enough for use as separate units), severely limited air support and a small expeditionary navy that would be dependant on friendly ports. Actually most support would come from local forces or the employer. It would probably be best practice to continue acting relatively independently from the various employers (as seen here, started by John Monash) so pragmatism stays high and Australia’s interests are represented (also in case the employers turn out to be idiots), and as a Vietnam Vet once told me ‘We went in with 16 helicopters and came back with 17’.