Western air operations have proven to be overwhelmingly successful in recent years - it's only when we failed to recognise our limitations and tried establishing democracies that our problems began, writes Alan Stephens.

Prime Minister Tony Abbott's announcement that the RAAF has joined the air campaign against Islamic State should be greeted by Australians with a mixture of quiet satisfaction and concern.

Satisfaction because we're doing the right thing; concern because it's not clear if our Government understands the strictly limited end-state the campaign can achieve.

There are two compelling reasons for taking military action against IS. The first is that the West, including Australia, carries much of the blame for the disaster that's currently engulfing Iraq and Syria. The ill-considered US-led invasions of Afghanistan in 2001-2 and Iraq in 2003 destabilised the entire Middle East and facilitated the rise of extremists. We were the midwives of this mess, and now we need to try to clean it up.

The second reason falls under the United Nations-sponsored doctrine of the 'Responsibility to Protect' (R2P), which argues that if a state cannot defend its population from genocide, war crimes, and crimes against humanity, then the international community has an obligation to intervene. IS represents a belief system remote from any notion of human decency and must be stopped sooner rather than later.

We should, incidentally, ignore those professional critics who complain that the West observes R2P selectively, which of course it does. States do what they can, when they can. As it happens, in this instance, the circumstances are favourable. Both the international political will and the military means - including, importantly, air strike forces from several Arab nations - are in place, so we must take the opportunity and meet our responsibility.

A military intervention will never 'win' the fight against IS, and nor will it generate an acceptable political resolution. But if applied within strictly controlled and clearly defined parameters, an air campaign can stop IS's bloody progress and buy time for the Middle East to regroup and look for longer-term solutions.

That's why, in what is an extraordinarily complex and difficult situation, an air campaign is our least-worst option.

If there's any one thing the West should have learned from its series of disastrous invasions over the past half-century (Vietnam, Iraq twice, Afghanistan), it's that extended occupations don't work. Based on the false premise that foreign soldiers can 'win hearts and minds' and 'fight amongst the people', they have instead alienated local populations and provided a ready source of psychological and propaganda material for their enemies (body bags, allied war crimes, captured soldiers on social media, etc).

By contrast, in recent decades, carefully constructed air campaigns backed up to a greater or lesser extent by local ground forces who actually can 'fight amongst (their own) people' have represented the West's single greatest military comparative advantage. On no less than six occasions (Iraq in 1991 and 2003, the former republic of Yugoslavia in 1995 and 1999, Afghanistan in 2001-2, and Libya in 2011), Western air operations have been overwhelmingly successful.

Indeed, it was only when we put boots on the ground in Iraq and Afghanistan that our problems began.

It's worth recalling that in the most recent of those campaigns, the Libyan dictator Moamar Gaddafi's army was within days of victory over its revolutionary opponents, and British prime minister David Cameron feared a 'bloody massacre' in Benghazi. NATO air power stopped Gaddafi's army in its tracks and made possible the rebel forces' eventual victory.

Which leads to another crucial lesson.

Confusion as to whom the West should or shouldn't support has been a constant within the byzantine world of Middle Eastern politics since World War II. Have 'our' dictators - Saddam, Gaddafi, Assad, the Saudi royal family, Mubarak, etc - been better or worse bets than 'their' bewildering array of religious/populist movements?

It's been on the shoals of that near-intractable political/social/ethical dilemma that our maladroit military interventions have foundered.

The point here is that while things in post-Gaddafi Libya might be a mess, because we didn't invade - because we didn't put Western boots on the ground - it's their mess, not ours. In effect, NATO fought and won a just, R2P campaign in Libya, and it's now up to the Libyans to decide for themselves what kind of polity they want. And that's as it should be.

The unambiguous end-state of the campaign Australia has joined should be to stop and to contain IS, by degrading its ability to mass and manoeuvre in force, to employ heavy weapons and armoured vehicles, and to seize territory and population centres. Once that's been achieved, we can expect IS's many Arab enemies increasingly to resist and to push back, especially since they're now being armed by the West.

It should not be our end-state to establish democracy, or bring about regime change, or anything remotely similar. The concern is that it's not clear whether our politicians, including the Opposition, understand that.

Dr Alan Stephens is a Canberra-based historian and a former RAAF pilot. View his full profile here.