As Graney points out there are better and cheaper ways to resolve youth unemployment such as additional funding for traineeships, apprenticeships, wage subsidies and other assistance. While the free-marketeers could solve it by removing minimum wages and allowing youth to bid wages down to a level which supported full-employment.
This then begs the question of what purpose national service would be performing?
- Weight loss and fitness - seems a bit of an over kill
- Discipline and respect for authority - seems to be something which schools and parents should be providing. And providing at a far lower cost.
- A larger body of trained soldiers - for when China/Indonesia invades?
At it's core the national service proposition seems to rest upon nationalistic principles. That is a belief that war will be visited upon us by our enemies and that we should use war as a foreign policy tool. This situation would require a disciplined society and large pool of trained soldiers - which is precisely the purpose of national service.
This kind of nationalism and real politik is by now uncommon in the developed world and unlikely to see a resurgence in the near future. And even if it did the context is so different that the large army which national service provides would be of minimal use.
If developed countries went to war with each other the fighting would tend to be short and sharp as the conflict rapidly escalated to a nuclear confrontation. This wouldn't be a WWI or WWII where Australia would recruit, train and deploy to Europe. In all likelihood it would be over before we could get any serious forces on the ground (even if we flew soldiers in their tanks, vehicles, supplies, etc would need to be shipped).
If Australia went to war against a developing country then a larger army may be required to participate in a shooting war and then occupy the country - but seriously does anyone see this happening? The world will flash back to the 19th Century and colonialism will be back in vogue? Even if we tried the developing world is such that we would be mauled. Examples include USSR in Afghanistan, US in Iraq, US in Vietnam, US in Somalia, etc etc.
If a developing country went to war against Australia then what would they do? Firstly they have to get here which basically means they need many large transport vessels which developing countries don't have. Even if they did have them we could target them en route using our air force and navy - which doesn't require a large number of people. Even if they managed to land it would most likely be the Northern approaches. Lets assume they level Darwin, then what? They march to Sydney? The logistical issues would be insurmountable.
Realistically the military operations which Australia is likely to engage in are peace keeping missions in our region - which don't require large numbers of soldiers. Deployments with our larger allies abroad - which don't require large numbers. Maintaining air and sea superiority on our approaches - this requires slightly larger numbers but is within our current capacity.
In short, even without looking at the cost of national service in dollars and freedom we can reject it as an anachronism of a bygone era, out of place in Australia today.
PS: will reconsider national service when we need to colonise the galaxy and fight bad ass aliens.